Frequency relay SPAF 140 C

Not active product since 2011

The frequency relay SPAF 140 C is used for the protection of power generators and other AC equipment against overfrequency and underfrequency. The operation of the relay can be based on the definite time principle, on the rate of frequency change principle, or on a combination of these two principles. In generator protection applications the relay protects the generator and the prime mover against hazardous overspeeding and/or underspeeding. The relay can also be used for the protection of large synchronous motors in networks where automatic network restoration is used. The relay isolates the motor from the network in the event of an outage, averting dangerous unsynchronized connection.


  • Overfrequency and underfrequency relay with four frequency stages

Product benefits

  •  Motor asset protection

Product features

  • Overfrequency and underfrequency relay with four frequency stages
  • Each frequency stage can be set for definite time overfrequency or underfrequency function
  • Each frequency stage can also be set for positive or negative frequency-rate-of-change (df/dt) function
  • The definite time operating principle and the rate of change operating principle can be combined
  • Each frequency stage can be given two separate operate times
  • Adjustable undervoltage blocking level
  • Field-adjustable relay rated frequency
  • The protection stages can be separately blocked via external blocking inputs
  • High system reliability due to continuous self-supervision
  • Member of the SPACOM product family and ABB’s Distribution Automation system

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