Who wants to strain, spend their money and time on re-equipment of devices and mechanisms that already work perfectly? As practice shows, many do. Although not everyone in life encounters industrial equipment equipped with powerful electric motors, they constantly encounter, albeit not so voracious and powerful, electric motors in everyday life. Well, everyone probably used the elevator.
Electric motors and loads - a problem?
Probably the most significant load placed on the engine at the time of start-up is a multiple, albeit short-term, excess of the rated operating current of the unit. After just a few seconds of operation, when the electric motor reaches its normal speed, the current consumed by it will also return to normal levels. To ensure the necessary power supply have to increase the power of electrical equipment and conductive lines, which leads to their rise in price.
When starting a powerful electric motor, due to its high consumption, the supply voltage “drops”, which can lead to failures or failure of equipment powered from the same line. In addition, the service life of power supply equipment is reduced.
If emergency situations occur that result in engine burnout or severe overheating, properties of transformer steel may change so much so that after repair the engine will lose up to thirty percent of its power. Under such circumstances, it is no longer suitable for further use and requires replacement, which is also not cheap.
Why do you need a soft start?
It would seem that everything is correct, and the equipment is designed for this. But there is always a “but”. In our case there are several of them:
- at the moment of starting the electric motor, the supply current can exceed the rated one by four and a half to five times, which leads to significant heating of the windings, and this is not very good;
- starting the engine by direct switching leads to jerks, which primarily affect the density of the same windings, increasing the friction of the conductors during operation, accelerates the destruction of their insulation and, over time, can lead to an interturn short circuit;
- the aforementioned jerks and vibrations are transmitted to the entire driven unit. This is already completely unhealthy, because may cause damage to its moving parts: gear systems, drive belts, conveyor belts, or just imagine yourself riding in a jerking elevator. In the case of pumps and fans, this is the risk of deformation and destruction of turbines and blades;
- We should also not forget about the products that may be on the production line. They may fall, crumble or break due to such a jerk;
- Well, and probably the last point that deserves attention is the cost of operating such equipment. We are talking not only about expensive repairs associated with frequent critical loads, but also about a significant amount of inefficiently spent electricity.
It would seem that all of the above operating difficulties are inherent only in powerful and bulky industrial equipment, however, this is not so. All this can become a headache for any average person. This primarily applies to power tools.
The specific use of such units as jigsaws, drills, grinders and the like require multiple start and stop cycles over a relatively short period of time. This operating mode affects their durability and energy consumption to the same extent as their industrial counterparts. With all this, do not forget that soft start systems cannot regulate engine speed or reverse their direction. It is also impossible to increase the starting torque or reduce the current below that required to start rotating the motor rotor.
Video: Soft start, adjustment and protection of the commutator. engine
Options for soft start systems for electric motors
Star-delta system
One of the most widely used starting systems for industrial asynchronous motors. Its main advantage is simplicity. The engine starts when the windings of the star system are switched, after which, when the normal speed is reached, it automatically switches to delta switching. This is the starting option allows you to achieve a current almost a third lower than when starting an electric motor directly.
However, this method is not suitable for mechanisms with low rotational inertia. These, for example, include fans and small pumps, due to the small size and weight of their turbines. At the moment of transition from the “star” to the “triangle” configuration, they will sharply reduce the speed or stop altogether. As a result, after switching, the electric motor essentially starts again. That is, in the end, you will not only not achieve savings in engine life, but also, most likely, you will end up with excessive energy consumption.
Video: Connecting a three-phase asynchronous electric motor with a star or triangle
Electronic motor soft start system
A smooth start of the engine can be done using triacs connected to the control circuit. There are three schemes for such connection: single-phase, two-phase and three-phase. Each of them differs in its functionality and final cost, respectively.
With such schemes, usually it is possible to reduce the starting current up to two or three nominal. In addition, it is possible to reduce the significant heating inherent in the aforementioned star-delta system, which helps to increase the service life of electric motors. Due to the fact that the engine starting is controlled by reducing the voltage, the rotor accelerates smoothly and not abruptly, as with other circuits.
In general, engine soft start systems are assigned several key tasks:
- the main one is to reduce the starting current to three to four rated ones;
- reducing the motor supply voltage, if appropriate power and wiring are available;
- improvement of starting and braking parameters;
- emergency network protection against current overloads.
Single-phase starting circuit
This circuit is designed to start electric motors with a power of no more than eleven kilowatts. This option is used if it is necessary to soften the shock at start-up, but braking, soft starting and reducing the starting current do not matter. Primarily due to the impossibility of organizing the latter in such a scheme. But due to the cheaper production of semiconductors, including triacs, they have been discontinued and are rarely seen;
Two-phase starting circuit
This circuit is designed to regulate and start motors with a power of up to two hundred and fifty watts. Such soft start systems sometimes equipped with a bypass contactor to reduce the cost of the device, however, this does not solve the problem of phase supply asymmetry, which can lead to overheating;
Three-phase starting circuit
This circuit is the most reliable and universal soft start system for electric motors. The maximum power of motors controlled by such a device is limited solely by the maximum temperature and electrical endurance of the triacs used. His versatility allows you to implement a lot of functions, such as: dynamic brake, flyback pickup or balancing of magnetic field and current limiting.
An important element of the last of the mentioned circuits is the bypass contactor, which was mentioned earlier. He allows you to ensure the correct thermal conditions of the electric motor soft start system, after the engine reaches normal operating speed, preventing it from overheating.
The soft start devices for electric motors that exist today, in addition to the above properties, are designed to work together with various controllers and automation systems. They have the ability to be activated by command from the operator or the global control system. Under such circumstances, when the loads are turned on, interference may appear that can lead to malfunctions in the automation, and therefore it is worth paying attention to protection systems. The use of soft start circuits can significantly reduce their influence.
Do-it-yourself soft start
Most of the systems listed above are actually not applicable in domestic conditions. Primarily for the reason that at home we extremely rarely use three-phase asynchronous motors. But there are more than enough commutator single-phase motors.
There are many schemes for smooth starting of engines. The choice of a specific one depends entirely on you, but in principle, having a certain knowledge of radio engineering, skillful hands and desire, it is quite you can assemble a decent homemade starter, which will extend the life of your power tools and household appliances for many years.
Scope of application and functions
To start and stop household pumps, the EXTRA Aquacontrol soft starter UPP-2.2S 220 V is widely used. The device is used in relation to vibration and centrifugal electric pumps. In addition, the device has proven itself in working with asynchronous and commutator electric motors. It can also control lighting and heating devices, provided that the maximum power specified in the instructions is not exceeded.
The main function of UPP-2.2S is to eliminate hydraulic and mechanical shocks that may occur during pump startup. The device also prevents pump breakdowns resulting from power surges.
Principle of operation
EXTRA Aquacontrol UPP-2.2S is controlled via a signal cable. The developers have equipped the device with protection against low and high voltage. If the voltage exceeds 252 V, the pump will be turned off automatically. After the voltage stabilizes to 245 V, the pump turns on again. When the lower pressure threshold of 160 V is reached, the pump will also be turned off. As soon as the voltage rises above 160 V, the pump will automatically start. The duration of the soft start depends on the type of pump: vibration – 2 sec; centrifugal – 3-7 sec.
Operating Requirements
The EXTRA Aquacontrol device must be installed in a closed room where there is no artificial climate control. The manufacturer prohibits applying voltage to the signal cable. UPP-2.2S cannot be used to control the operation of a pumping station without a hydraulic accumulator. Remember, turning the pump on and off with a period of less than 60 seconds will damage the device.
It is strictly forbidden to operate the device if the housing is damaged or with the cover removed. You cannot repair or disassemble the UPP-2.2S yourself. If all the rules set out in the instructions are followed, the service life of EXTRA Aquacontrol UPP-2.2S is 5 years. The device housing should be inspected annually for damage to the housing.
How to achieve optimal energy savings in hydraulic systems with centrifugal pumps? This question today increasingly arises among specialists and business managers. So which devices can shorten the payback period and increase energy efficiency - soft starters, variable frequency drives or the use of parallel pump control? The authors of the article offer a carefully conducted analysis of various technical solutions, illustrated with examples of implementation in production, diagrams and tables.
ABB LLC, Moscow
Ensuring energy efficiency is one of the most pressing and at the same time complex tasks at the present time. Reducing energy consumption costs is one of the methods for increasing production profitability and efficient operation of production lines. A general analysis of plants in a wide range of applications shows that the costs associated with equipment purchases and production downtime due to maintenance and commissioning of new equipment can be partially offset by savings in energy consumption.
Energy efficient technologies are one of ABB's priorities. The most modern methods and developments to ensure the most efficient operation are used in modern ABB equipment - frequency converters and soft starters*, which are widely used to control the drive mechanisms of pumping units and can significantly reduce energy consumption at water treatment and wastewater treatment facilities.
The often used mechanical method of controlling pump flow, or throttling method, is extremely ineffective in terms of energy savings. This raises the question: which of the two technical solutions is the most economical method of reducing energy consumption - variable frequency drives or cyclic control (Fig. 1)? Essentially, the characteristics of the hydraulic system in which the centrifugal pump is used is the determining factor in choosing one control method over the other.
Rice. 1. Regulation of system flow through throttling, cyclic and frequency control
In the wastewater industry, centrifugal pumps are typically switched on/off under the control of a process control system. Residual water (that is, water coming from residential or commercial buildings) is usually collected in septic tanks or wastewater tanks until it is pumped to municipal water treatment plants. Taking into account some frequency, the use of soft starters significantly reduces the risk of pump clogging with waste contained in the water.
Cyclic control is an interesting alternative to variable frequency drives, despite the loss of flexibility in flow control. In other words, the soft starter is considered a suitable and competitive technology to protect the induction motor from electrical overloads, mechanical shock and vibration during start-up, as well as water hammer in the piping system that occurs when the pump stops. In addition, the electric motor is operated at its optimal operating point and switched off for the rest of the time.
The following sections provide an analysis of the energy savings and ROI of variable frequency control and cyclic control solutions for two centrifugal pumps (90 kW and 350 kW).
Typical pumping system
When designing a pumping system, the main condition is to ensure the required flow rate Qop [m3/h]. In an ideal system, the selected pump has a characteristic Qbep [m3/h] that matches the characteristic Qop [m3/h]. In practice, a larger pump is usually selected (Fig. 2). As a result, the pump operates with reduced hydraulic efficiency over most of the performance range. The above is illustrated in Fig. 3 for two Aurora centrifugal pumps with rated power of 90 kW and 350 kW.
Table 1. Comparative characteristics of the parameters of two pumps
Rice. 2. Selecting a pump for an industrial installation
Rice. 3. Reduction in hydraulic efficiency in 90 kW and 350 kW pumps due to changes in system component parameters by 15%
To analyze the possibilities for saving energy in these pumps, three different hydraulic systems were considered: with a predominance of pressure to overcome friction, that is, the ratio (?) of the static pressure Hst [m] to the maximum hydraulic height Hmax [m] is 5%; with a predominance of static pressure (? is 50%); with combined pressure (? is 25%) (Fig. 4).
Rice. 4. Hydraulic systems selected to analyze potential energy savings
Performance characteristics of frequency converter, soft starter and motor
Frequency converters have a high efficiency (ηconv), which naturally decreases when the output power decreases relative to the rated value. When the soft starter operates in steady state, that is, when the bypass is activated, the efficiency of soft starters is almost 100%. It should be noted that the efficiency of soft starters decreases noticeably with an increase in the number of starts per hour and a reduction in operating time intervals, which is due to additional Joule losses when starting and stopping the electric motor, as well as the operation of thyristors (Fig. 5).
Rice. 5. Change in electrical efficiency (%) of soft starter and frequency converter with pumping load
The recently adopted more stringent standards (IE classes) guarantee increased efficiency of the electric motor - when operating under load (Fig. 6 and 7). The efficiency of the electric motor (strictly depending on the class) is affected by the use of either a frequency converter or a soft starter: the efficiency decreases when powered by a high-speed output inverter due to the presence of harmonic distortions in current and voltage, but does not change when powered by a soft starter after the end of the transient process acceleration due to the sinusoidal voltage waveform at the device output.
Rice. 6. The influence of the energy efficiency class of an electric motor on the efficiency of the pump
Rice. 7. Changing the efficiency of an electric motor with a hydraulic load
The effect of changing the characteristics of system components, the energy efficiency class of the electric motor and harmonic losses in a real system is given in Table. 2.
Table 2. Impact of larger system size, motor class and harmonic losses
for electricity consumption (Pn =90 kW – switching frequency 4 kHz)
Energy Saving
The energy savings achieved using frequency and cyclic control in 90 kW and 350 kW pumping systems are shown in Fig. 8 and 9. In systems with a predominance of pressure to overcome friction (? = 5%), frequency control provides higher energy savings over almost the entire operating range (from 7 to 98%) for both pumping systems. In the case of a 90 kW pump and in a system with a predominant static head (? = 50%), cyclic control is a better technical solution compared to using a frequency converter for all operating points. The frequency converter provides slightly higher energy savings for a 350 kW pump, but only in the range of 75 to 92% of pump capacity. When considering a combined hydraulic system (? = 25%), VFD control only allows higher energy savings for pumps with capacities above 28% (for a 90 kW system) and 24% (for a 350 kW system). In fact, the highest energy savings using frequency control are observed in the 15 to 20% pump capacity range.
Rice. 8.
for pump 90 kW
Rice. 9. Energy savings [%] with frequency and cyclic control
for pump 350 kW
Unlike frequency converters, in which there are losses on semiconductor components during nominal operation, soft starters, in this case, operate through a bypass contactor, so thyristors are not involved (Fig. 10). And therefore, there are no additional heat losses. Operational and system characteristics for which it is preferable to choose one or another control method to regulate pump performance are shown in Fig. eleven**.
Rice. 10. Optimal efficiency for a 90 kW pump when bypassed through a soft starter
at high loads (90–100% of design capacity)
Rice. eleven. The reference point at which the savings when using cyclic control become higher is
than using a variable frequency drive solution
Return on Investment
One of the most important factors for customers is calculating the return on investment, which includes additional costs due to equipment downtime during installation and commissioning of the soft starter.
The cost of a frequency converter is three times higher than the cost of a soft starter for pumps with a rated power of up to 25 kW, and for pumps of 350 kW - five times. The total initial investment for frequency regulation or cyclic control is calculated as the sum of the cost of the frequency converter or soft starter plus the percentage of downtime costs relative to the costs spent over the entire life cycle of the process line.
For frequency converters and soft starters, this share is 7.5%.
The cost of individual components may vary for several reasons. First of all, it should be noted that low-voltage frequency converters are more often used in continuous operation of the electric motor, rather than in start/stop mode, and provide more accurate control. However, insulated gate bipolar transistors (IGBTs) used in frequency converters require maintaining a certain temperature regime and cooling, which makes them quite expensive elements and accordingly increases the cost of frequency converters compared to soft starters of the same rated power. In soft starters, semiconductor power elements - thyristors - operate only in start and stop modes with an average time of each mode of about 15 seconds. It is worth noting that inexpensive and reliable thyristors do not require constant forced cooling.
The payback period for frequency converters and cyclic flow control is shown in Fig. 12 and 13 for electric motors 90 kW and 350 kW for three hydraulic systems: ? = 5%, 25% and 50%.
Rice. 12. Payback period for solutions with frequency and cyclic control (soft starter)
for pump 90 kW
Rice. 13. Payback period for solutions with frequency and cyclic control (soft starter)
for pump 350 kW
Parallel Pump Control Solutions
In many hydraulic systems, optimal energy savings with a good return on investment can be achieved by using a parallel pump control system*** that uses both variable speed drives and soft starters.
Rice. 14. Solution for a system with four parallel pumps
(hydraulic system with a predominance of pressure to overcome friction)
Table 3. Control diagram for a system with four parallel pumps
In hydraulic systems with a predominance of pressure to overcome friction (? = 5%) and with four parallel pumps - each pump with a rated power of 350 kW (2500 m3/h) - it is optimal to use two frequency converters and two soft starters (Fig. 14). In a design that provides the best solution for cost-effectiveness and control flexibility, two pumps, 1 and 2, are controlled by soft starters, and pumps 3 and 4 are controlled by frequency converters (see Table 3). Pumps with soft starters operate at maximum performance. By increasing the rotation speed of pumps controlled by frequency converters to the nominal speed, maximum system performance can be ensured. In a mixed hydraulic system (static pressure/friction dominant hydraulic system) (? = 25%), the design that provides the optimal solution in terms of return on investment and control flexibility is three pumps, the first two of which are controlled soft starters, and the third pump - a frequency converter (see Fig. 15 and Table 5).
Rice. 15. Solution for a system with three parallel pumps
(hydraulic system with static pressure/predominant pressure to overcome friction)
Table 4. Flow control diagram for a system with three parallel pumps
(combined hydraulic system)
For both systems, the initial investment in purchasing soft starters and frequency converters transforms into economic profit in less than 1.5 years, provided that the regulated flow is less than 80% of the total performance (Fig. 16).
Table 5. Options
Rice. 16. Estimated payback period for two installations,
with parallel control of pumps from frequency converters and soft starters
The best decision?
An analysis of the effectiveness of frequency and cyclic flow control systems was carried out for two centrifugal pumps (90 kW and 350 kW) with motors up to 1000 V. The results obtained indicate that control through frequency control is the best solution in hydraulic systems with a predominance of pressure to overcome losses for friction (transportation of liquid without height difference in the case of using circulation pumps). In systems where static pressure predominates, it is recommended to use cyclic control. Frequency converters should be avoided in applications with flat pump and load characteristics due to the risk of instability and breakdown.
Soft start devices are the most promising technical solution for water treatment and wastewater treatment plants, in which it is necessary to turn on/off the pump to pump liquid out of collectors and subsequently move wastewater to treatment facilities. Soft starters are highly reliable and have built-in functions to eliminate water hammer both when starting and stopping the system. However, maximum energy savings and minimum payback periods for a wide range of hydraulic systems can be achieved by using parallel pump control circuits that use a combination of frequency converters and soft starters. Based on automation know-how and a wide range of low-voltage automation equipment, ABB offers other solutions for efficient use of energy in a wide range of applications.
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* Soft starters regulate the voltage level supplied to the electric motor, thereby ensuring smooth starting and stopping of the drive.
** When converting percentage energy savings (for fixed speed and throttling) into cost efficiency, the pump is assumed to run 8,760 hours per year (330 x 24) at $0.065 per kWh of electricity.
*** For optimal flow control, parallel circuits operate one pump until maximum flow is achieved, after which the hydraulic load is divided between two pumps running simultaneously. When the second set point is reached, three pumps are activated, and so on.
Literature
1. ITT Industries (2007). ITT’s Place in the cycle of water: Everything but the pipes.
2. Aurora Pump (Pentair Pump Group) June 1994, United States.
3. IEC 60034-31:2009. Rotating electrical machines. Part 31: Guide for the selection and application of energy-efficient motors including variable speed applications.
4. Brunner, C. U. (4–5 February 2009). Efficiency classes: Electric motors and systems. Motor energy performance standards event, Sydney (Australia). www.motorsystems.org.
5. Department of Energy (DOE). Energy International Agency (EIA) (June 2009). Average retail price of electricity to ultimate customers.
6. Sagarduy, J. (January 2010). Economic evaluation of reduced voltage starting methods. SECRC/PT-RM10/017.
7. Hydraulic Institute (August 2008). Pumps & Systems, Understanding pump system fundamentals for energy efficiency. Calculating cost of ownership.
8. ITT Flygt (2006). Circulationspumpar med vet motor för värmesystem i kommersiella byggnader.
9. Vogelesang, H. (April 2009). Energy efficiency. Two approaches to capacity control. World Pumps Magazine.
The ES024 series is produced by Effective Systems control stations, capable of combining up to 7 pumps with a rated power from 1.5 to 315 kW, a rated voltage of 380 V into a single system. According to the customer’s technical specifications, it is possible to manufacture control stations other rated powers and voltages.
Depending on the customer’s needs for pump control stations produced by the company "Effective Systems" the following functions can be implemented:
- Setting up to 8 different preset pressure levels that need to be maintained, distributed by time of day;
- The ability to switch the system to “sleep mode” in the absence of water intake or when there is little water intake, which can significantly reduce energy consumption;
- Periodic replacement of pumps to ensure their uniform wear and avoid rusting of backup pumps;
- Control of drainage pumps, allowing you to control the level of wastewater;
- Determining the liquid level and controlling the filling of the tank, allowing you to start the pump depending on the amount of liquid in the tank and replenish its flow at a given supply level;
- Alarm about high and low pressure in the pipeline;
- Storing current parameters of up to 7 pump motors into memory to provide current protection and overload protection for any pump operating at any given time;
- Fault diagnostics, which allows you to automatically identify and exclude faulty pumps from the system operation algorithm.
To receive a technical and commercial proposal, contact us using one of the methods indicated at the top and bottom of this page.
BRIEF REFERENCE: SOFT START OF PUMPS
In practice, the starting current of pump electric motors is 3-5 or more times higher than the rated current. This ultimately leads to increased thermal wear of the insulation of the stator windings (because of this, the service life and reliability of the pump motor are significantly reduced). In addition, if the power of the supply network is insufficient, a short-term voltage drop is possible, and this can negatively affect the operation of other electrical equipment powered from the same network.
Direct start of the pump is harmful both for the unit and for the well as a whole, as it is accompanied by water hammer, which destroys the shut-off valves, the pipeline and the pump itself. When the well pump is started directly, a strong influx of water from the water layer can be observed and this leads to the destruction of the filter zone, and, consequently, to the entry of sand into the well.
The only effective solution to these problems is to implement soft start of the pump, for which a number of technical means have been developed, including soft starters and frequency converters.
The task of soft starters is to provide protection for pumping units from high starting current, mechanical overloads, water hammer, i.e. ensure durability and reliable operation of the equipment. Along with solving the problem of soft starting, the use of frequency converters when operating pumps makes it possible to match the pump performance with the flow rate of the pumped liquid at each moment in time, which can significantly reduce the energy consumption of the system.
There are many reasons for turning on household pumps through a soft starter.
Typically, a submersible or surface pump is connected via an electromechanical or electronic relay, an automation unit or a magnetic starter. In all of the above cases, mains voltage is supplied to the pump by closing the contacts, that is, through a direct connection. This means that we supply full mains voltage to the stator windings of the electric motor, and the rotor is not yet rotating at this time. This leads to the appearance of an instantaneous powerful torque on the pump motor rotor.
This connection diagram is characterized by the following phenomena when starting the pump:
Current surges through the stator (and, accordingly, through the supply wires), since the rotor is short-circuited.
In a simplified understanding, we have a short circuit on the secondary winding of the transformer. In our experience, depending on the pump, manufacturer and shaft load, the pulse starting current can exceed the operating current from 4 to 8 times, and in some instances up to 12 times.
A sudden appearance of torque on the shaft.
This has a negative impact on the starting and operating stator windings, bearings, ceramic and rubber seals, significantly increasing their wear and reducing their service life.
The appearance of a sharp torque on the shaft leads to a sharp rotation of the well pump housing relative to the pipeline system.
We have repeatedly witnessed how, because of this, a well pump was disconnected from the pipelines and fell into the well. In the case of a pumping station based on a surface pump installed on a hydraulic accumulator platform, this leads to loosening of the fastening nuts and destruction of the weld points and seams of the hydraulic accumulator. Also, when the pump is turned on directly, the service life of the water supply and shut-off valves is reduced, especially at the points of their connection.
It is generally accepted that a hydraulic accumulator eliminates water hammer in the water supply system.
This is true, but water hammer disappears in pipelines only starting from the point where the hydraulic accumulator is connected. In the gap between the pump and the hydraulic accumulator, when the pump is directly connected, the hydraulic shock remains. As a result, in the interval from the pump to the accumulator we have all the consequences of water hammer on all parts of the pump and on the pipeline system.
In water filtration systems, water hammer that occurs when the pump is directly connected significantly reduces the service life of the filter elements.
If the local power grid weak, then your neighbors will also know that a pump with a power of more than 1 kW is running when directly connected by a sharp drop in voltage in the network at the moment the pump is turned on.
If local network EXTREMELY WEAK, and your neighbor also enjoys life by connecting all available electrical appliances to the network, then a well pump submerged to great depths may not start. Such a voltage surge can damage electronic devices connected to the network. There are known cases when, when the pump was started, an expensive refrigerator stuffed with electronics failed.
The more often the pump is turned on, the shorter its service life.
Frequent starts through direct connection lead to failure of the plastic couplings of well pumps connecting the electric motor to the pumping part.
We went over the problems that arise when starting a pump without soft start devices (SPD) .
It should be noted that even when turning off the pump without SCP There are some negative aspects with a direct connection diagram:
When the pump is turned off, a water hammer also occurs in the system, but now due to a sharp decrease in torque on the pump shaft, which is tantamount to the creation of an instant vacuum.
A sharp decrease in torque on the pump shaft also leads to rotation of the pump housing, but in the opposite direction.
Let's think about the pipelines and threaded connections of the pump.
In conventional household pumps, electric motors are asynchronous and have a pronounced inductive nature.
If we abruptly interrupt the flow of current through an inductive load, then there is a sharp jump in voltage across that load due to the continuity of the current. Yes, we open the contact and all the high voltage should remain on the pump side. But with any mechanical opening of the contact, the so-called “contact bounce” is present, and high voltage pulses enter the network, and therefore also enter the devices connected to the network at that time.
Thus, when the pump is directly connected, there is increased wear on the mechanical and electrical parts of the pump (both during startup and shutdown). Devices included in the same network also suffer, and the service life of filtration systems and plumbing fittings is reduced.
Usage soft start devices (“Aquacontrol UPP-2.2S”) allows you to smooth out most of the shortcomings described above. In device UPP-2.2S a specially calculated voltage rise curve on the pump has been implemented, which allows, on the one hand, to reliably start the pump in the most unfavorable operating conditions, and on the other hand, to smoothly increase the shaft rotation speed. This device also has built-in protection against low and high voltage mains to protect the pump from extreme operating conditions and switching on.
IN UPP-2.2S phase triac control is used. At the moment of starting, a part of the mains voltage is supplied to the pump, which creates a torque sufficient to ensure that the pump starts. As the rotor spins, the voltage on the pump gradually increases until the voltage is fully applied. After this, the relay turns on and the triac turns off. As a result, when using UPP-2.2S the pump is connected to the network through relay contacts, that is, the same as with a direct connection. But for 3.2 seconds (this is the soft start time), voltage is supplied to the pump through a triac, which ensures a “soft start”, without sparks at the relay contacts.
With such a start, the maximum starting current exceeds the operating current by no more than 2.0-2.5 times instead of 5-8 times. Using UPP-2.2S, we reduce the starting load on the pump by 2.5-3 times and extend the life of the pump by the same amount, ensuring more comfortable operation of devices connected to the electrical network. UPP-2.2S can be called a device with resource-saving technology.
