Powerful PTC Motor Protection

PTC Motor Protection

Electric motors are heated both due to their natural structure and due to their working conditions. The heat generated in the motor can cause irreversible damage to the motor and its windings. Therefore, electric motors must be protected against temperature. More sophisticated protection methods have started to be preferred due to the classical life protection methods, their low lifetime, high space coverage and low price performance rates.

Why WAGO PLC Digital Input Module?

  • It can be connected to PTC thermistors with 2-wire connection technology according to DIN 44081/44082 standards.
  • 6 PTC thermistors can be connected in series to a single channel. Each channel can be armed and disarmed on demand.
  • It shows the related channel error status in case of short circuit, open circuit, cable break, out of measuring range.
PTC Motor Protection

Figure 1: Example of 1, 3 and 6 PTC serial resistance curves

  • Thermal monitoring of the engine or engine parts (such as bearings) can be performed.
  • Overload protection can be done without using any internal components.
  • Input signals, limit values and filter parameters can be adjusted.
  • Space saving in the control cabinet. (only 12 mm width)
  • High price / performance ratio.
PTC Motor Protection

Figure 2: PTC Digital Input Module has one LED green and red status per channel to indicate overtemperature, short circuit and open circuit and cable faults.


Why Not a Motor Protection Relay?

Thermal monitoring cannot be performed with thermal protection relay. Also, open circuit and short circuit status information cannot be obtained.

  • Traditional motor protection such as mines, arc furnaces operating at maximum load is not long life. The contacts wear out quickly as they open under excess amperage.
  • The protection relays occupy a large space in the control cabinets.
  • No overload protection can be provided without using any internal components.
WAGO 750-451 and 750-450 support all standard RTD sensors.


You may also like...

1 Response

  1. July 3, 2020

    […] Protection Class Should I […]

Leave a Reply

Your email address will not be published. Required fields are marked *