ABB Circuit Shield Relay

[moosewl]

I have an old ABB Circuit Shield 51 relay that has gone bad. It has control voltage of 175VDC. If I find another relay, same model but with a different control voltage, does anyone know of a way to modify the relay to accept 175VDC control voltage?

 

[davidbeach]

175? Are you sure? I've seen lots of weird old stuff, lots of different control voltages, but I've never seen 175VDC. Are you sure it isn't 125VDC?

 

[moosewl]

Yes 175. This is the oddball substation on site. All others are 125

 

[davidbeach]

Good luck.

 

[rasevskii]

for moosewl:

I second davidbeach. There must be a mistake, no one uses 175VDC, the standard DC voltages for control power around the world are 125VDC and 250VDC. Sometimes 125 volt is referred to as 110V, but the usual voltage is 125 or even 135...

Please read the nameplate again, or if you are actually on the site, measure the battery voltage. We could be wrong of course...

rasevskii

 

[JG2828]

Actually it does come in a 175vdc version
<1> Each of the listed style numbers contains an X for the control voltage
designation.
To complete the style number replace the X with the proper control
voltage code digit:
175 Vdc (120 Vac Capacitor Trip) Type 423 only...................... 1
350 Vdc (240 Vac Capacitor Trip) Type 423 only...................... 2
48 Vdc............................................................. 3
125 Vdc............................................................. 4
250 Vdc Type 423 only............................................... 5
120 Vac Type 443 only............................................... 6
32 Vdc............................................................. 8
24 Vdc............................................................. 9
20-150 Vdc/30-150 Vac Type 443 only................................. 0

 

[JG2828]

These are still manufactured by ABB in Coral Springs, FL. Give them a call at 1-800-523-2620. Maybe customer service can assist you with your question.

 

[DTR2011]

most Circuit Shield Relays have a voltage dropping power resistor on the back (gold -Dale - 50W). This is used to adapt various control voltages to an internal standard voltage.

I want to say that the relay takes 48V DC, as you will find the resistors on 125V models. I used to work for ABB and tested quite a few in the past. I had a stash of the resistors for this purpose.

 

[Zogzog]

I might have one of those, I have a ton of these but only a couple 175VDC, what is the full CAT#?

 

[moosewl]

Cat# 223P2210

I've been thinking about putting a resistor on the voltage input of the relay to drop the 175VDC down to 125VDC. Any thoughts on this?

 

[Zogzog]

Don't have any of those in stock, these guys can usually repair them.

http://www.solidstaterepair.com/

 

[JG2828]

moosewl (Electrical)
"I've been thinking about putting a resistor on the voltage input of the relay to drop the 175VDC down to 125VDC. Any thoughts on this?"

I'm not sure thats the best idea. I would think the relay would draw more current when tripping then it does when idle. This would cause your voltage drop across the resistor to change.

 

[davidbeach]

If the resistor is only in series with the relay power supply, it shouldn't be a problem. If there is trip current through the resistor, then yes, a mess.

 

[moosewl]

Thanks for the help. It looks like the DC powers the relay and also is connected to the trip circuit.

 

[rasevskii]

mooseewl:

The trip circuit is obviously connected solidly to the DC supply input on the relay terminal no. 7, therefore you cannot put a resistor in series with this supply. When the trip operates the external trip coil will draw far more current than the relay electronics and the DC voltage available to the relay will drop.
That will certainly cause a maloperation of the protection.

The resistor which adapts the relay to various voltages must be internal inside the relay and is not shown on the diagram available to the buyer. Can someone confirm this?

This was designed for a solid DC supply, (according to the PDF that you provided).You have to look at the whole scheme, perhaps the 175V version has some other connection diagram special to that application.

rasevskii

 

[jghrist]

The instruction bulletin indicates that the 175 volt model is for circuits with a capacitor trip device. Is there a separate dc source or is the relay powered from the capacitor trip rectifier circuit?

I would certainly not assume that inserting a resistor in the circuit would provide a sufficient power supply for a lower rated dc relay. You would need some sort of regulated dc supply.

 

[moosewl]

smallgreek - would you happen to have or know where to get a schematic of the relay that would show this resistor?

 

[rasevskii]

moosewl:

If you actually have the defective relay on the table, why not just open it up (unplug the relay from the case) and locate the resistor connected internally from terminal 7. It would be a relatively high wattage power resistor, easily identified. Measure or read off the ohm value, then order a 125V relay from ABB, and replace the resistor in that one with the resistor from your 175V one. Assuming that your present relay is not totally carbonized toast...

Not at all a correct procedure, but a temporary fix if you are desperate or so far out in the bush that there is no other way.

I used to be involved with these Circuit Shield relays occasionally when I worked in the field, and they are easy to deal with. The traces on the PC board are easy to follow, unlike some other mfrs designs.

rasevskii