alternating relay
alternating relay
(OP)
I need to know how to change a float controlled lead-lag pump control into an alternating pump controller?
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RE: alternating relay
The basic idea is that you need something that can "remember" which pump was the last to run. The old alternators were specifically designed for this.
You can still have a lead-lag scheme if both pumps need to run at times. The alternator just changes which pump starts first.
Talk with any MCC or motor starter manufacturer - I'm sure they can provide typical schematics.
RE: alternating relay
These operate like a child's see-saw. There are two actuating coils and an armature rocks one way or the other. A small permanent bias magnet keeps the armature "stuck" in whatever position was last energized. The relay therefore "remembers" even after both coils are completely de-energized.
So you have an "on" coil, and an "off" coil and usually one or more sets of changeover contacts just like any normal relay. By cross coupling the contacts and coils it can be made to alternate every time it is energized.
RE: alternating relay
RE: alternating relay
RE: alternating relay
Link to brochure
Link to diagram
There are other simple electronic alternators made by Diversified Electronics, SSAC, Time Mark etc., all good as well, but this one is by far the least number of wires to do the job and the least expensive.
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dpc (Electrical)
I can't believe they still make these things. I like it. Thanks, jraef for a free trip down memory lane.
jraef (Electrical)
Unfortunately, I'm sure some marketing genius at Siemens will someday question that decision and eliminate them, but for now, I think they still sell a lot of them. Because the design and tooling is already paid for, I'd imagine they are cheap to make.
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RE: alternating relay
RE: alternating relay
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Member, P3
Read the Eng-Tips Site Policies at FAQ731-376
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