Electrical: Phase failure Relay

randheerp · Mar 24, 2012

Hi All,

We are using Phase Failure Relay (Minilec: D1VMR1) in one of our AMF application. We are now facing a problem like, Phase Failure Relay returns supply to the incomer R-Y-B. this return supply is passed to indication light and the lights will be ON the even if any of the phase fails. Connection diagram is attached...

How to deal with it?

keithkyll · Mar 24, 2012

Are the lights Neon?
1) Add a .1 uF, 1KV ceramic capacitor in series with each lamp.
2) Disconnect neutral - let it float.

iant · Mar 24, 2012

as the lights are supplied by L1 L2 and L3
when supply is returned the lights will come back on.
the Phase falure relay output contacts need to go somewhere.
If you want to turn the lights off and keep them off after a failure you need to have a contactor in series with your lights and tied into the Phase failure relay.

Saffa · Mar 24, 2012

To me, this looks like your phase fail relay has no neutral and hence it's possible for current to flow from one phase, through a measurement coil in the phase fail relay, through two lamps and back to another phase.

I would use a different phase fail relay, one which is interally star connected (i.e. has a neutral wire) and is measuring phase to neutral voltage. We use the C-MAC RP33 in all our boards, it's a basic phase to neutral voltage only (i.e. no phase sequence or frequency detection) but does the job for us.

http://www.carrel-electrade.co.nz/relays/rly1.htm

randheerp · Mar 26, 2012

@Saffa:: I think, wot u said is the problem, it is a Delta connected PFR. Now we have to work around coz we have already purchased it.

@iant:: The nomal voltage of a phase is 230V. When I OFF the R phase, the R phase light is still ON coz it is getting around 60V. So we used a 230V relay, but too didn't work.

@keithkyll: Yes I am planing to test with this.

ThankU all...........

nonuke · Mar 26, 2012

Since you have a Phase failure Relay, why not use only one indicator light which will go on when the failure relay is OK
and will go off when not OK or vice-versa. Since you have 2 aux. contacts, you can use one for this purpose.

randheerp · Mar 26, 2012

@nonuke: ya, but to differentiate R-Y-B fail and a single Phase fail won't be possible...

nonuke · Mar 26, 2012

randheerp said:
@nonuke: ya, but to differentiate R-Y-B fail and a single Phase fail won't be possible...

In my opinion, if you know there is a phase missing by looking at the light, it will not be hard to find out which phase is missing just by using a voltemeter or a simple voltage tester.

GlennA · Mar 27, 2012

Phase fail detect

If your purpose is to send a fault signal if a phase drops out, use the contacts of the phase monitor - that is what they are for. If instead this is for troubleshooting, your tech should be able to find the missing leg with a meter.

randheerp · Mar 27, 2012

Oh ok...... Thanks

Electrical: Phase failure Relay

randheerp

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