DC voltage protectors provide continuous surveillance of the monitored
voltage circuit, typically a battery supply or charging circuit. When the
measured voltage moves outside the set point limits, the relay will
operate after the selected time delay or differential, giving an alarm
and/or initiation signal. The protectors offer protection for under-voltage,
over-voltage and battery level control.
Operation
DC voltage protectors offer user adjustable trip point (set point) and time delay settings.
The time delay setting adjustment range is typically 0 to 10 seconds, although longer
delays up to 30 seconds are available. As soon as the monitored signal moves outside
of the set point limit, the time delay is activated, after which a trip will occur. The time
delay prevents the relay from tripping for a predetermined period to prevent nuisance
tripping. The products also feature an internal differential (hysteresis) setting of 1% to
reduce nuisance tripping if the measured signal is noisy or unstable. The units draw
their operating power from the measuring inputs.
Over-Voltage Models
When the monitored voltage exceeds the set point, the time delay is started. When the
time has elapsed, the relay will energise and the red LED will illuminate to indicate the
trip condition. The relay will automatically reset once the monitored voltage falls below
the set point minus the differential. When reset, the LED will extinguish and the relay
de-energises. The time delay is not active when resetting.
Under-Voltage Models
When the monitored voltage falls below the set point, the time delay is started.
When the time has elapsed, the relay will de-energise and the red LED will extinguish
to indicate the trip condition. The relay will automatically reset once the monitored
voltage rises above the set point plus the differential. When reset, the LED will
illuminate and the relay energises. The time delay is not active when resetting.
Options
250 series protector relays offer various customised options to suit individual
requirements.
- Adjustment ranges – different adjustment ranges are possible for the set point and
time delay controls.
- Differential – internally fixed value between 1% and 15%.
- Relay operation – standard models are fail safe, but the relays can be customised
to energise or de-energise on trip.
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