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Overload relays

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

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

€26.78 +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
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21264DB1 Separate positioning Screw connection CLASS 10
Special offer

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

€28.63 +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
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21161AB0 Direct attachment Screw connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21161AB0 Direct attachment Screw connection CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21161AB0
  • EAN: 4011209781597
  • Mounting method: Direct attachment
  • 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
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21160BC1 Separate positioning Spring clamp connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160BC1 Separate positioning Spring clamp connection CLASS 10

€26.78 +VAT
PLN 124.49
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160BC1
  • EAN: 4011209782143
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Spring clamp connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21160EC0 Direct attachment Spring clamp connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160EC0 Direct attachment Spring clamp connection CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160EC0
  • EAN: 4011209781962
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Spring clamp connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21264PC1 Separate positioning Spring clamp connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21264PC1 Separate positioning Spring clamp connection CLASS 10

€41.13 +VAT
PLN 191.24
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21264PC1
  • EAN: 4011209781306
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Spring clamp connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB24834AA1 Separate positioning AC
Special offer

Electronic overload relay Siemens 3RB24834AA1 Separate positioning AC

€199.86 +VAT
PLN 929.26
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB24834AA1
  • EAN: 4011209863040
  • Mounting method: Separate positioning
  • Release class: Other
  • Voltage type for actuating: AC
  • Number of auxiliary contacts as normally closed contact: 0
  • Number of auxiliary contacts as normally open contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21160GC0 Direct attachment Spring clamp connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160GC0 Direct attachment Spring clamp connection CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160GC0
  • EAN: 4011209781986
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Spring clamp connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21161JC0 Direct attachment Spring clamp connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21161JC0 Direct attachment Spring clamp connection CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21161JC0
  • EAN: 4011209782105
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Spring clamp connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB23834AC1 Separate positioning
Special offer

Electronic overload relay Siemens 3RB23834AC1 Separate positioning

€149.16 +VAT
PLN 693.51
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB23834AC1
  • EAN: 4011209642010
  • Mounting method: Separate positioning
  • Release class: Other
  • Number of auxiliary contacts as normally closed contact: 2
  • Number of auxiliary contacts as normally open contact: 2
  • Number of auxiliary contacts as change-over contact: 0
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB31234NB0 Separate positioning Screw connection Adjustable
Special offer

Electronic overload relay Siemens 3RB31234NB0 Separate positioning Screw connection Adjustable

€85.06 +VAT
PLN 395.48
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB31234NB0
  • EAN: 4011209749597
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Screw connection
  • Release class: Adjustable
  • Number of auxiliary contacts as normally closed contact: 1
  • Number of auxiliary contacts as normally open contact: 1
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB30361UB0 Separate positioning Screw connection CLASS 10
Special offer

Electronic overload relay Siemens 3RB30361UB0 Separate positioning Screw connection CLASS 10

€75.42 +VAT
PLN 350.64
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB30361UB0
  • EAN: 4011209936287
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Screw connection
  • Release class: CLASS 10
  • Number of auxiliary contacts as normally closed contact: 1
  • Number of auxiliary contacts as normally open contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21264EB1 Separate positioning Screw connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21264EB1 Separate positioning Screw connection CLASS 10

€41.13 +VAT
PLN 191.24
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21264EB1
  • EAN: 4011209781054
  • 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
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21264EB0 Direct attachment Screw connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21264EB0 Direct attachment Screw connection CLASS 10

€34.61 +VAT
PLN 160.89
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21264EB0
  • EAN: 4011209780989
  • Mounting method: Direct attachment
  • 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
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21364RB0 Direct attachment Screw connection CLASS 10 A
Special offer

Thermal overload relay Siemens 3RU21364RB0 Direct attachment Screw connection CLASS 10 A

€60.72 +VAT
PLN 282.33
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21364RB0
  • EAN: 4011209916791
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Screw connection
  • Release class: CLASS 10 A
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB20661GC2 Separate positioning CLASS 10
Special offer

Electronic overload relay Siemens 3RB20661GC2 Separate positioning CLASS 10

€150.37 +VAT
PLN 699.14
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB20661GC2
  • EAN: 4011209638389
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Other
  • Release class: CLASS 10
  • Number of auxiliary contacts as normally closed contact: 1
  • Number of auxiliary contacts as normally open contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21160EJ0 Direct attachment CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160EJ0 Direct attachment CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160EJ0
  • EAN: 4011209782396
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Other
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21160CC0 Direct attachment Spring clamp connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160CC0 Direct attachment Spring clamp connection CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160CC0
  • EAN: 4011209781948
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Spring clamp connection
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB30262RB0 Separate positioning Screw connection CLASS 20
Special offer

Electronic overload relay Siemens 3RB30262RB0 Separate positioning Screw connection CLASS 20

€54.06 +VAT
PLN 251.33
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB30262RB0
  • EAN: 4011209749160
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Screw connection
  • Release class: CLASS 20
  • Number of auxiliary contacts as normally closed contact: 1
  • Number of auxiliary contacts as normally open contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21264CJ0 Direct attachment CLASS 10
Special offer

Thermal overload relay Siemens 3RU21264CJ0 Direct attachment CLASS 10

€22.54 +VAT
PLN 104.76
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21264CJ0
  • EAN: 4011209781436
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Other
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21161JJ0 Direct attachment CLASS 10
Special offer

Thermal overload relay Siemens 3RU21161JJ0 Direct attachment CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21161JJ0
  • EAN: 4011209782532
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Other
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21261GJ0 Direct attachment CLASS 10
Special offer

Thermal overload relay Siemens 3RU21261GJ0 Direct attachment CLASS 10

€22.54 +VAT
PLN 104.76
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21261GJ0
  • EAN: 4011209781375
  • Mounting method: Direct attachment
  • Type of electrical connection of main circuit: Other
  • Release class: CLASS 10
  • Max. rated operation voltage Ue [V]: 690
  • Number of auxiliary contacts as normally closed contact: 1
EL
Response time: usually up to 2 days
Thermal overload relay Siemens 3RU21160JB0 Direct attachment Screw connection CLASS 10
Special offer

Thermal overload relay Siemens 3RU21160JB0 Direct attachment Screw connection CLASS 10

€20.97 +VAT
PLN 97.46
  • Manufacturer: Siemens
  • Manufacturer Code: 3RU21160JB0
  • EAN: 4011209781573
  • Mounting method: Direct attachment
  • 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
EL
Response time: usually up to 2 days
Electronic overload relay Siemens 3RB30261RB0 Separate positioning Screw connection CLASS 10
Special offer

Electronic overload relay Siemens 3RB30261RB0 Separate positioning Screw connection CLASS 10

€46.09 +VAT
PLN 214.30
  • Manufacturer: Siemens
  • Manufacturer Code: 3RB30261RB0
  • EAN: 4011209749108
  • Mounting method: Separate positioning
  • Type of electrical connection of main circuit: Screw connection
  • Release class: CLASS 10
  • Number of auxiliary contacts as normally closed contact: 1
  • Number of auxiliary contacts as normally open contact: 1
EL
Response time: usually up to 2 days
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Overload Relays

Overload relays are devices used in control circuits of electrical devices, usually motors. Their primary, overriding purpose is to stop (disconnect) the machine in the event of an overload, thus protecting it from damage. Overload relays also prevent the occurrence of other overload effects, in particular fires.

Overload Relays - Protection of motors and other temperature sensitive equipment

Wherever electrical equipment requires protection against overheating, overload protection devices are used. In industry, it is particularly important to protect motors, which are costly and important components of production systems.

Functions of overload relays

In order to guarantee the proper performance of motors, overload relays, which belong to current-dependent protective devices, are used among other things. This means that the relay monitors the current in the motor winding supply cables and disconnects the control circuit if the current exceeds a set value. Excessive increase in current in a certain period of time indicates an increase in temperature of the motor winding, which may be caused by:

  • overload,

  • motor stalling,

  • loss of one of the phases.

In each case, the relay will detect the overload, disconnecting the circuit and providing protection against damage to the machine.

What is an overload?

The most common cause of motor temperature rise is motor overloading, which is generally the flow of current through an electrical device that exceeds the rated current of that device. Short-term overloading is not dangerous, but prolonged overloading causes excessive heat generation. A prolonged process results in a large increase in temperature because the heat release is proportional to the square of the amperage and the time the overload occurs. In other words, the longer the overload, the more heat generated by the current.

Overloads are dangerous for electrical equipment because they cause overheating and can lead to reduced mechanical strength, short circuits and fires.

Thermal and electronic overload relays

Thermal overload relays are manufactured as mechanical and electronic devices. They perform the same task but differ in construction.

Thermal overload relays

Thermal overload relays use a characteristic property of bimetals to change their form and state when exposed to temperature. When a certain temperature is reached, the auxiliary contact of the device is switched. The bimetal is heated by the relay resistors, through which the motor current flows. The balance between heat input and heat output is determined by the specific current for the specified temperatures. When the tripping temperature is reached, the relay will trigger. It is important that the tripping time depends on the current and the load on the relay. It has to be smaller than the time of danger for the motor insulation, but the minimum times for the limit current and for the motor standstill state are also defined in order to avoid unjustified tripping of the relay.

Electronic overload relays

Electronic overload relays, as well as thermal overload relays using bimetals, belong to the group of current-dependent devices. The detection of the motor current flowing through the three main wires (in three-phase units) is realized by means of separate current transducers or the so-called Rogowski coil. Triggering occurs, similar to a thermal relay, due to an increase in current and the relay controls overload, phase loss in the motor and asymmetrical current consumption.