MSF220VL, PTC-Resistor-Relay for dry transformers, Fan - Alarm - Trip - Trip (core)

MSF220VL, PTC-Resistor-Relay for dry transformers, Fan - Alarm - Trip - Trip (core)
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  • T221674
PTC-Relay, 4 PTC-circuits Test-button, fan-control monitoring of core no tripping when switching... more

PTC-Resistor-Relay for dry transformers, 4 PTC-circuits, intelligent fan control, monitoring of core temperature


The MSF220VL is particularly suitable for monitoring of temperatures at dry transformers, when also the temperature of the core shall be measured. Monitoring of core temperature is especially required in rectifier transformers because of harmonics causing heat in the core.

An intelligent control prolongs automatically the runtime of a cooling-fan, depending on the load of the transformer. Each PTC-circuit is monitored for break and short circuit. This reduces probability of false alarms. Relays in operating-current mode prevent from a trip-signal when switching on supply voltage.

The device can be adapted to different applications with 4 programs:

  1. Fan-control - alarm - trip (winding) - trip (core)
  2. Alarm - trip (winding) - trip (core) - alarm (fault)
  3. Fan-control - alarm - trip (winding) - alarm (fault)
  4. Fan-control with hysteresis T1/T2 - alarm – trip (winding) - time relay

Overview of functions

  • 4 inputs for PTC
  • Intelligent control of fan
  • Automatic fan-test 1x / week
  • electronic reclosing lock for alarms (trip) connectable
  • Monitoring of sensors
  • Test-button
  • Simple testing with disconnectable monitoring of break and short circuit (for 10 minutes)
  • cURus
  • LEDs for alarms, states of relays and sensors
  • Housing for mounting on DIN-Rail or wall-mount(option)
  • Mounting height 55 mm
  • Universal supply voltage AC/DC 24-240 V
  • DEWA-standard for Dubai
  • Accessory: Front mounting kit type ER4


Technical data

Rated supply voltage Us


AC/DC 24 - 240 V ± 15 %, < 5 VA


Connectable PTC resistors


4 x 1...6 PTC according to DIN VDE V 0898-1-401 (formerly DIN 44081/82)


Switching point


< 4000 Ω


Output relay


4 x 1  change-over-contact (co)


Type of contact


Type 2 (see general technical information)


Test conditions


see general technical information


Rated ambient temperature


-20...+60 °C


Dimensions h x w x d


Design V4: 90 x 70 x 58 [mm]




on 35 mm DIN rail according to EN 60 715 or screws M4


Protection Housing/Terminals






approx. 250 g

Input / measuered parameter: Measuring input PTC
Outputs: Alarms/relays
Design: Mount in switchgear cabinet, Mount in circuit breaker box
Approvals: UL/CSA
Extras: ≥ 4 sensor inputs, Reclosing lock
Applications: Wind energy plants, Protection of transformers