Westinghouse DA-50 trip unit - old
Westinghouse DA-50 trip unit - old
(OP)
Hello,
I am working in a facility that has some older vintage electrical equipment and I am trying to figure out a trip unit on a Westinghouse DA-50 1600A breaker. Does any one have any information on these? What are or how to find the settings? It has not been maintained and I need to build a case for replacement but want to understand what I have first.
Thank you
I am working in a facility that has some older vintage electrical equipment and I am trying to figure out a trip unit on a Westinghouse DA-50 1600A breaker. Does any one have any information on these? What are or how to find the settings? It has not been maintained and I need to build a case for replacement but want to understand what I have first.
Thank you






RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
If you're looking to convert to a modern trip unit, put this phrase in Google exactly as I've typed it:
westinghouse "da-50" "trip unit"
You'll get lots of hits for folks selling retrofit trip units.
Best to you,
Goober Dave
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RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
Lots of options for upgrades, I have about 150 DA-50's in stock with many different upgraded trip units from older amptectors to modern AC PRO's. There are also 3 upgrade kits we install on these to ammend performance issues over the years.
A refirbished and retrofitted replacement is your least painfull option, there are modern retrofills available for these but retrofills lead to more possible failures from the cradles they install as well as very rare and unique parts of repairs are needed in the future.
RE: Westinghouse DA-50 trip unit - old
Does this mean that the 11th reprinting of the manual was in 1952?
Agree with dpc on the dashpots. You may consider cleaning and re-oiling the dashpots immediately. The oil viscosity is part of the calibration. I would use transformer oil if you are setting for fairly quick action and W30 (single viscosity, not 10W-30) motor oil if you are setting for a long delay.
Instant trip settings are 100%, 125% 150%, 175% and 200%.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Westinghouse DA-50 trip unit - old
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Westinghouse DA-50 trip unit - old
"Will work for (the memory of) salami"
RE: Westinghouse DA-50 trip unit - old
Best to you,
Goober Dave
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RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
RE: Westinghouse DA-50 trip unit - old
The picture says a lot. The oily substance seen on the left and center dashpots is the dashpot oil used for inverse time delay. Under overcurrent conditions, these trips will operate with little or no time delay. That is assuming that they operate at all. In many cases, after years of inactivity the series trip mechanism will become frozen by lack of lubrication and/or rust.
The same can be true for the breaker mechanism itself. In many cases, the mechanism on an old breaker like this will be frozen shut from rust, corrosion, and lack of lubrication. Try pushing the "open" button on one and see what happens. If you are lucky and the breaker does open, it may not latch closed again.
I would not recommend trying to rebuild the dashpots. Their operation is based on the use of springs to determine pickup and dashpot oil to provide the delay. Potential problems include weak springs, improper oil viscosity, and worn or damaged dashpot seals. If you were to attempt a rebuild, it would be necessary to setup the breaker on a high current test set to perform the calibration and testing.
I agree with zogzog's suggestion that replacing the breakers with rebuilt units featuring updated trip units is an option but, as he pointed out, maintaining the units in reliable condition will be problematic.
Another concern is interrupting ability. If the line side transformer (or incoming utility service) has been replaced since the 1950's, then it would be necessary to be certain that the available short circuit current does not exceed the breaker rating of (if memory serves me correctly) 50,000 amps. Keep in mind that this rating is for a "new" breaker. Weakening of the opening springs over time can reduce the short circuit interrupting capacity. Of course, if the incoming transformer has not been replaced since the 1950's then that is another big problem of its' own.
This brings to mind another question, is the rest of your distribution system just as old??
Finally, although most electrical types do not care about this; the phase barriers between the dashpots as well as the arc chutes are made of asbestos. Usually the environmental types go nuts when they find out about this.
RE: Westinghouse DA-50 trip unit - old
Re the environmental types; They probably would not appreciate a label;
"Caution do not inhale this circuit breaker!"
It is a good flag to get the environmental department to push for replacement.
Bill
--------------------
"Why not the best?"
Jimmy Carter