Which ssr to use for industrial 480VAC?

jtiii

I am using the Stamp PLC. Its outputs are rated at 24VDC with a max 800ma per output.
The guy I am building this for says the motors are 1/2 horse 480V 3Phase.
I am going to be controlling 6 of them. Will I need to buy 3 SSRs per motor?
I see lots of 3PST regular relays, but maybe I am missing the SSRs or
don't understand the terminology...
Any thoughts would be highly appreciated.

Thanks in advance,
John Tapper

Bruce Bates

John -

I've looked for multi-pole SSR's and I've never found any. That's NOT to say they don't exist.

If I were doing this project, I would use 3 phase contactors (relays) if the motors already have overload protection. If they do not have overload protection, I would use 3 phase starters. Both have three sets of contacts. In either case, you would use one per motor.

That's really the only proper way to do it and be in compliance with the NEC if this is an effort being made in the US. Other countries may have different governing agencies.

Regards,

Bruce Bates

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Involvement and committment can be best understood by looking at a plate of ham and eggs. The chicken was involved, but the pig was committed. ANON

QuattroRS4

http://www.omega.com/pptst/SSR3PH.html


http://radionics.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294959982&Ntt=3+phase+ssr&Ntk=I18NAll&Nr=AND%28avl%3aie%2csearchDiscon_ie%3aN%29&Ntx=mode%2bmatchallpartial&N=4294954844+4294890343&Nty=1&selectAttribute=48%20-%20530Vac#breadCrumb


a few links to 3phase SSR's

Regards,
·········· John Twomey

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'Necessity is the mother of invention'

Chris Savage

Is this for a BASIC Stamp application?

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Chris Savage
Parallax Tech Support

jtiii

Thanks both.
I went out to the plant today and learned a little about 3-phase motors. Bruce, they do have starters, so I would just need a relay to control the coil of the starter.
Now that we are talking about needing MUCH LESS current, the field widens considerably.

Thanks,
John Tapper

Bruce Bates

John -

It may well be even easier and less costly then you think now! If the starters are like most 3 phase starters, you can simply add a remote or cover mounted, control station.

This control station can be any type that you might care to use. Some examples are: START (one button), STOP (one button), START-STOP (2 buttons), FWD-REV-STOP (3 buttons), START-JOG-STOP (3 buttons), UP-DOWN-STOP (3 buttons), etc.

Check the inside of the cover on the starter which is where most manufacturer's place instructions for the various control stations available. Barring that, grab a copy of the Motor Control Catalog for the manufacturer in question.

Regards,

Bruce Bates

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Involvement and committment can be best understood by looking at a plate of ham and eggs. The chicken was involved, but the pig was committed. ANON