Cheap Millisecond Timer

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Ingenieur

Senior Member
Location
Earth
DC breakers look at DCmV shunts. If you apply appropriate signal levels into the trip unit and the breaker operates within the prescribed time, that is the full extent of any secondary-injection test. No difference here.

Gar, I appreciate the thought that went into that explanation, but I am only looking for an off the shelf solution for the timer.

give a pn for a dc breaker
what is the application? Mining, elevator, photovoltaic, traction, ups/converters?
current/voltage range

we use a lot of dc breakers in mining
never saw one that tripped on mV?
 

ELA

Senior Member
Occupation
Electrical Test Engineer
COTs or no COTs

COTs or no COTs

I heard you say you wanted an off the shelf solution.
In my work there is often a need for a test that is somewhat unique and there may not be a cheap solution unless you are willing to do a little bit of extra work.
If you were interested in a fairly short learning curve an Arduino is a useful tool that you can customize to meet different test requirements. I always prefer an off the shelf solution. Just in case you do not find what you need.

http://www.instructables.com/id/How-to-get-an-Arduino-micros-function-with-05us-pr/
 

Aleman

Senior Member
Location
Southern Ca, USA
I have used a few of the smart relay type PLCs for various projects. I like these because they can be programmed without a laptop and sometimes you
really don't need an expensive full blown PLC. I looked and IDEC makes some of these styles that include 100khz high speed counters. I haven't used
the IDECs of this style but their stuff is cheap. Look to be around the $150 mark. Have USB outputs that could work with a laptop or etc. If I was trying
to do what you're doing I would most likely go this route. Or use some other PLC with a small HMI and a box.

IDEC FT1A-H12RA or B12RA B12RA
 

Ingenieur

Senior Member
Location
Earth
We use a scope if we need accurate data
a 225 A cb with uv trip
a Bender rcma423 gf relay holding the uv in, ct on a cb load pole
a contactor that put an adjustable 0-15 A thru the cb (we use a 15 A ngr)

a push button energized the contactor to apply the i
the contactor output was one scope input
the other the cb load out

relay response
uv drop out
cb contact opening

All in 1.5 cycle
15A at a 3A trip setting
 
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