merXu
Cancel

Control and protection of electric motors

(14,701 results)
Sort by
Power contactor, AC switching Siemens 3RT20162SB42 DC Spring clamp connection
Special offer

Power contactor, AC switching Siemens 3RT20162SB42 DC Spring clamp connection

€16.95 +VAT
PLN 79.58
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT20162SB42
  • EAN: 4011209846715
  • Voltage type for actuating: DC
  • Type of electrical connection of main circuit: Spring clamp connection
  • Rated operation current Ie at AC-1, 400 V [A]: 22
  • Rated operation current Ie at AC-3, 400 V [A]: 9
  • Rated operation power at AC-3, 400 V [kW]: 4
Supplier:
EL
Response time: usually up to 1 day
Contactor relay Siemens 3RH24311BM40 DC Screw connection
Special offer

Contactor relay Siemens 3RH24311BM40 DC Screw connection

€49.89 +VAT
PLN 234.31
  • Manufacturer: Siemens
  • Manufacturer Code: 3RH24311BM40
  • EAN: 4011209850217
  • Voltage type for actuating: DC
  • Connection type auxiliary circuit: Screw connection
  • Rated operation current Ie, 400 V [A]: 3
  • Number of auxiliary contacts as normally closed contact: 1
  • Number of auxiliary contacts as normally open contact: 3
Supplier:
EL
Response time: usually up to 1 day
Thermal overload relay Siemens 3RU21160CB1 Separate positioning Screw connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160CB1 Separate positioning Screw connection CLASS 10

€26.51 +VAT
PLN 124.49
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160CB1
  • EAN: 4011209781726
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Screw connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT10562AD36 AC/DC Rail connection
Special offer

Power contactor, AC switching Siemens 3RT10562AD36 AC/DC Rail connection

€287.49 +VAT
PLN 1,350.39
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT10562AD36
  • EAN: 4011209582231
  • Voltage type for actuating: AC/DC
  • Type of electrical connection of main circuit: Rail connection
  • Rated operation current Ie at AC-1, 400 V [A]: 215
  • Rated operation current Ie at AC-3, 400 V [A]: 185
  • Rated operation power at AC-3, 400 V [kW]: 90
Supplier:
EL
Response time: usually up to 1 day
Thermal overload relay Siemens 3RU21264DB1 Separate positioning Screw connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21264DB1 Separate positioning Screw connection CLASS 10

€28.34 +VAT
PLN 133.11
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21264DB1
  • EAN: 4011209781030
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Screw connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT20463KB40 DC Screw connection
Special offer

Power contactor, AC switching Siemens 3RT20463KB40 DC Screw connection

€175.81 +VAT
PLN 825.81
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT20463KB40
  • EAN: 4047621026992
  • Voltage type for actuating: DC
  • Type of electrical connection of main circuit: Screw connection
  • Rated operation current Ie at AC-1, 400 V [A]: 130
  • Rated operation current Ie at AC-3, 400 V [A]: 95
  • Rated operation power at AC-3, 400 V [kW]: 45
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT20182AP61 AC Spring clamp connection
Special offer

Power contactor, AC switching Siemens 3RT20182AP61 AC Spring clamp connection

€19.77 +VAT
PLN 92.86
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT20182AP61
  • EAN: 4011209896550
  • Voltage type for actuating: AC
  • Type of electrical connection of main circuit: Spring clamp connection
  • Rated operation current Ie at AC-1, 400 V [A]: 22
  • Rated operation current Ie at AC-3, 400 V [A]: 16
  • Rated operation power at AC-3, 400 V [kW]: 7.5
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT20262DB40 DC Spring clamp connection
Special offer

Power contactor, AC switching Siemens 3RT20262DB40 DC Spring clamp connection

€53.39 +VAT
PLN 250.76
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT20262DB40
  • EAN: 4047621051086
  • Voltage type for actuating: DC
  • Type of electrical connection of main circuit: Spring clamp connection
  • Rated operation current Ie at AC-1, 400 V [A]: 40
  • Rated operation current Ie at AC-3, 400 V [A]: 25
  • Rated operation power at AC-3, 400 V [kW]: 11
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT14766AR36 AC/DC Rail connection
Special offer

Power contactor, AC switching Siemens 3RT14766AR36 AC/DC Rail connection

€781.97 +VAT
PLN 3,673.04
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT14766AR36
  • EAN: 4011209510135
  • Voltage type for actuating: AC/DC
  • Type of electrical connection of main circuit: Rail connection
  • Rated operation current Ie at AC-1, 400 V [A]: 690
  • Rated operation current Ie at AC-3, 400 V [A]: 170
  • Number of auxiliary contacts as normally open contact: 2
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT23172AP60 AC Spring clamp connection
Special offer

Power contactor, AC switching Siemens 3RT23172AP60 AC Spring clamp connection

€17.73 +VAT
PLN 83.26
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT23172AP60
  • EAN: 4011209944749
  • Voltage type for actuating: AC
  • Type of electrical connection of main circuit: Spring clamp connection
  • Rated operation current Ie at AC-1, 400 V [A]: 22
  • Rated operation current Ie at AC-3, 400 V [A]: 12
  • Rated operation power at AC-3, 400 V [kW]: 5.5
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT20171BB443MA0 DC Screw connection
Special offer

Power contactor, AC switching Siemens 3RT20171BB443MA0 DC Screw connection

€25.53 +VAT
PLN 119.89
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT20171BB443MA0
  • EAN: 4011209847262
  • Voltage type for actuating: DC
  • Type of electrical connection of main circuit: Screw connection
  • Rated operation current Ie at AC-1, 400 V [A]: 22
  • Rated operation current Ie at AC-3, 400 V [A]: 12
  • Rated operation power at AC-3, 400 V [kW]: 5.5
Supplier:
EL
Response time: usually up to 1 day
Combination of contactors Siemens 3RA23168XB301AH0 Reversing contactor AC Screw connection IP20
Special offer

Combination of contactors Siemens 3RA23168XB301AH0 Reversing contactor AC Screw connection IP20

€43.77 +VAT
PLN 205.56
  • Manufacturer: Siemens
  • Manufacturer Code: 3RA23168XB301AH0
  • EAN: 4011209835658
  • Function: Reversing contactor
  • Voltage type for actuating: AC
  • Type of electrical connection of main circuit: Screw connection
  • Degree of protection (IP): IP20
  • Degree of protection (NEMA): Other
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT23261AN20 AC Screw connection
Special offer

Power contactor, AC switching Siemens 3RT23261AN20 AC Screw connection

€34.97 +VAT
PLN 164.22
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT23261AN20
  • EAN: 4011209898653
  • Voltage type for actuating: AC
  • Type of electrical connection of main circuit: Screw connection
  • Rated operation current Ie at AC-1, 400 V [A]: 40
  • Rated operation current Ie at AC-3, 400 V [A]: 15.5
  • Rated operation power at AC-3, 400 V [kW]: 7.5
Supplier:
EL
Response time: usually up to 1 day
Combination of contactors Siemens 3RA23188XB301AB0 Reversing contactor AC Screw connection IP20
Special offer

Combination of contactors Siemens 3RA23188XB301AB0 Reversing contactor AC Screw connection IP20

€58.82 +VAT
PLN 276.29
  • Manufacturer: Siemens
  • Manufacturer Code: 3RA23188XB301AB0
  • EAN: 4011209835924
  • Function: Reversing contactor
  • Voltage type for actuating: AC
  • Type of electrical connection of main circuit: Screw connection
  • Degree of protection (IP): IP20
  • Degree of protection (NEMA): Other
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT12646AV36 AC/DC Rail connection
Special offer

Power contactor, AC switching Siemens 3RT12646AV36 AC/DC Rail connection

€601.26 +VAT
PLN 2,824.23
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT12646AV36
  • EAN: 4011209508781
  • Voltage type for actuating: AC/DC
  • Type of electrical connection of main circuit: Rail connection
  • Rated operation current Ie at AC-1, 400 V [A]: 330
  • Rated operation current Ie at AC-3, 400 V [A]: 225
  • Rated operation power at AC-3, 400 V [kW]: 110
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT12666AD36 AC/DC Rail connection
Special offer

Power contactor, AC switching Siemens 3RT12666AD36 AC/DC Rail connection

€857.53 +VAT
PLN 4,027.99
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT12666AD36
  • EAN: 4011209509108
  • Voltage type for actuating: AC/DC
  • Type of electrical connection of main circuit: Rail connection
  • Rated operation current Ie at AC-1, 400 V [A]: 330
  • Rated operation current Ie at AC-3, 400 V [A]: 300
  • Rated operation power at AC-3, 400 V [kW]: 160
Supplier:
EL
Response time: usually up to 1 day
Power contactor, AC switching Siemens 3RT20241AK643MA0 AC Screw connection
Special offer

Power contactor, AC switching Siemens 3RT20241AK643MA0 AC Screw connection

€22.79 +VAT
PLN 107.01
  • Manufacturer: Siemens
  • Manufacturer Code: 3RT20241AK643MA0
  • EAN: 4011209913998
  • Voltage type for actuating: AC
  • Type of electrical connection of main circuit: Screw connection
  • Rated operation current Ie at AC-1, 400 V [A]: 40
  • Rated operation current Ie at AC-3, 400 V [A]: 12
  • Rated operation power at AC-3, 400 V [kW]: 5.5
Supplier:
EL
Response time: usually up to 1 day
Combination of contactors Siemens 3RA24258XE321BB4 Star-delta contactor DC Screw connection IP20
Special offer

Combination of contactors Siemens 3RA24258XE321BB4 Star-delta contactor DC Screw connection IP20

€270.80 +VAT
PLN 1,271.96
  • Manufacturer: Siemens
  • Manufacturer Code: 3RA24258XE321BB4
  • EAN: 4011209838598
  • Function: Star-delta contactor
  • Voltage type for actuating: DC
  • Type of electrical connection of main circuit: Screw connection
  • Degree of protection (IP): IP20
  • Degree of protection (NEMA): Other
Supplier:
EL
Response time: usually up to 1 day
Didn't find what you were looking for? We will help you!

Control and protection of electric motors

Once the type of electric motor has been selected, the next step is to get the appropriate safety devices. This will help to prevent future failures of the particular work unit. It is therefore worthwhile to identify the hazards that could adversely affect the operation of the motor. It is therefore necessary to very carefully adjust the protections in the motors, taking into account the type of power supply. This will allow you to perfectly match the protective elements. They can also be easily controlled. The protections should also be matched to the design of the power supply.

Control and protection of electric motors: types of protection

The Control and protection of electric motors is the basis for the proper operation of all units. Therefore, it is useful to know the types of protection in order to match the right solutions to your electric motor. One of them is differential current protection, used for both single-phase and three-phase motors. This type of protection is short circuit and overload protection. The residual current protection protects not only the motor but also the supply system. In addition, it is also an electric shock protection. However, it should be borne in mind that such protection may not be used in every workplace. Remember about the residual current of residual current protection. Popularly referred to as "differential" will normally work on the difference of 30 mA in the power circuit. This is a small value, which in some industrial plants can escape from the supply circuit in damp halls where the motor has just started to drive certain equipment. Therefore, always check all environmental factors even before selecting a specific protection. When it is necessary to do so, choose residual-current protections operating at a higher residual current, for example at 300 mA.

The second type of protection used is the overcurrent protection. They should be selected when looking for effective short-circuit protection. Each overcurrent protection protects the motor with the power supply circuit from the effects of a short circuit that may occur. This type of protection should be adjusted in such a way that in case of currents flowing that value exceeds the long-term current-carrying capacity of conductors, the protection is not tripped before the moment of excessive temperature increase in conductors.

The tripping current of a protection must be specified as a multiple of the rated current together with the corresponding value of the coefficient of the overcurrent circuit breaker, where the coefficient of the current that triggers the protection device is assumed as the values 1.6 or 2.1 for fuse links and 1.45 for overcurrent circuit breakers

with characteristics B, C and D. Class C fuses are normally used to protect motors. These are designed for start-ups because they have a greater trip delay. Using the wrong class of overcurrent circuit breakers can lead to poor operation. Overcurrent protection is usually used as an initial means of short circuit protection for the motor, circuits and subsequent protection. The only thing to keep in mind is that using too many circuit breakers can cause the motor, circuit, or other protective devices to fail. Overcurrent circuit breakers are used to protect against short circuits and residual current circuit breakers are mainly used to protect people against electric shock.

Protection typical of a motor is a motor switch, also called a thermal switch or thermistor. Its abbreviation is PKZ - t. All motor circuit breakers are designed to connect, as well as protect circuits that disconnect the motor from the power supply during an overload. This determines the use of two types of protection in one device. The first is short circuit protection and the second is motor winding overload protection. When excessive temperature occurs on the motor windings, a thermal trip protects the motor from significant overheating. In addition, the motor will also be protected against phase loss. The motor circuit breaker should be adjusted to the extent that the rated current of the motor fits within the setting range of the motor circuit breaker. The motor circuit breaker is set to the rated current of the motor during normal operation.

Special protections such as dry-running protection, for suction or submersible pumps, may also be used. Additional protections include a phase loss detector. The motors can also be equipped with a voltage asymmetry detector. This is useful where several motors with higher power ratings are installed. Special protections also include inverters, i.e. frequency converters. Their task is to smoothly control the rotation of the motor. Based on the operating parameters of a particular unit, the inverters immediately detect failures.

Control of electric motors

The final control system for a specific motor depends on the type of motor, the expected application and the required level of monitoring. The controller is responsible for controlling direction, speed and also torque. It can create one or more control signals which are then amplified. A power driver is also used to provide motors with the correct level of power, the signal generated by the controller. Sensors, Sensors, are used to measure supply current level, position, temperature. Their job is to provide feedback to the controller, allowing for efficient and precise motor control. Usually Hall sensors, inductive sensors or encoders are used. Filtering systems are also used to reduce electromagnetic interference. Galvanic isolation is also used to separate the motor control system from the rest of the system to protect against surges or ground potential.