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FREQUENCY monitoring relays are used in circuits where equipment can be damaged if the voltage exceeds or falls below the normal level. Another common application is generators. The relay won't allow the emergency power to be connected until the correct number of cycles is present thus avoiding possible damage to equipment. |
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Type No |
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Description |
Under Frequency Relay |
Over Frequency Relay |
Under Frequency Relay |
Over Frequency Relay |
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Function |
Under Frequency |
Over Frequency |
Under Frequency |
Over Frequency |
Time Delay (from fault) |
≈1S |
≈1S |
≈200mS |
≈200mS |
Hysteresis |
≈1% |
≈1% |
0.3-3Hz |
0.3-3Hz |
Latch |
No |
No |
No |
No |
Output |
SPDT Relay |
SPDT Relay |
DPDT Relay |
DPDT Relay |
Output Rating |
8A @ 250VAC |
8A @ 250VAC |
8A @ 250VAC |
8A @ 250VAC |
Supply Voltage Un |
12, 48VAC/DC, 24VDC |
12, 48VAC/DC, 24VDC |
110, 230, 400VAC |
110, 230, 400VAC |
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24, 110, 220/240VAC |
24, 110, 220/240VAC |
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- |
Integral Transformer |
110, 220/240V only |
110, 220/240V only |
Yes |
Yes |
Monitoring Range |
35-70Hz |
35-70Hz |
40-60, 50-70Hz |
40-60, 50-70Hz |
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