3 Phase detection failure needed.

[athenanews]

Please can anybody suggest the best route for doing this. Ideally we would
like a simple flag to let us know if we lose any phases. The flag would need
to be in the form of a 5-12 volt DC signal out to control equipment.

Best regards Steve


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[scada]

Post by athenanews
Please can anybody suggest the best route for doing this. Ideally we would
like a simple flag to let us know if we lose any phases. The flag would need
to be in the form of a 5-12 volt DC signal out to control equipment.
Best regards Steve
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.669 / Virus Database: 431 - Release Date: 26/04/2004

Two relays rated at the phase to phase voltage. Wire the coil of relay1
across phases A-B. Wire the coil of relay2 across phases B-C. Wire the NO
contacts of each relay in series with both relays, and DC power supply
(5-12V). Now you will loose the 5-12V upon phase loss.

Also the industry uses three phase detectors. I'm not in my office now, but
a google search should show vendors!

If you want to monitor phase current for equality look for a "46 Relay"
(phase imbalance), it allows one to adjust the phase differential trip
point.

[scada]

Post by scada

Post by athenanews
Please can anybody suggest the best route for doing this. Ideally we would
like a simple flag to let us know if we lose any phases. The flag would

need

Post by athenanews
to be in the form of a 5-12 volt DC signal out to control equipment.
Best regards Steve
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.669 / Virus Database: 431 - Release Date: 26/04/2004

Two relays rated at the phase to phase voltage. Wire the coil of relay1
across phases A-B. Wire the coil of relay2 across phases B-C. Wire the NO
contacts of each relay in series with both relays, and DC power supply
(5-12V). Now you will loose the 5-12V upon phase loss.
Also the industry uses three phase detectors. I'm not in my office now, but
a google search should show vendors!
If you want to monitor phase current for equality look for a "46 Relay"
(phase imbalance), it allows one to adjust the phase differential trip
point.

In addition I should say, if the phase to phase voltage is to large for the
relay coil voltage, then a PT should be utilized. A PT (potential
transformer) is just a step-down transformer. It is a good idea to use in
any case because it offers isolation.

[glen herrmannsfeldt]

Post by scada

Post by athenanews
Please can anybody suggest the best route for doing this. Ideally we would
like a simple flag to let us know if we lose any phases. The flag would

(snip)

Post by scada
Two relays rated at the phase to phase voltage. Wire the coil of relay1
across phases A-B. Wire the coil of relay2 across phases B-C. Wire the NO
contacts of each relay in series with both relays, and DC power supply
(5-12V). Now you will loose the 5-12V upon phase loss.

You should check that the relays drop out with only two legs
active. There might still be enough to hold them in.

-- glen