RPC- ratings for contactor control switches

Krankieone · Sep 28, 2020

After a couple of years I have finally got around to building a control cabinet for my hastily thrown together RPC .I have ordered contactors for the pony and the idler and one for the power out .Having ordered switches some time ago only to have them arrive 12 weeks later and be self latching rather than momentary. I now find myself looking at switches again I want to find some with a short postage time that I know will be fit for purpose (once bitten) after looking closely at the listing for the ones I liked saw they were rated for 250v and 3amp and it occurred to me that I didn't know what the current draw for the contactor coils would be and after several hours of google searching I was none the wiser the largest contactor I plan to use is 65 amp 4 pole with a 240v coil (in Australia we run 240v single phase or 415 3phase).
Does anyone know how many amps these coils draw or the min rating for the control switches?

thermite · Sep 28, 2020

Krankieone said:
After a couple of years I have finally got around to building a control cabinet for my hastily thrown together RPC .I have ordered contactors for the pony and the idler and one for the power out .Having ordered switches some time ago only to have them arrive 12 weeks later and be self latching rather than momentary. I now find myself looking at switches again I want to find some with a short postage time that I know will be fit for purpose (once bitten) after looking closely at the listing for the ones I liked saw they were rated for 250v and 3amp and it occurred to me that I didn't know what the current draw for the contactor coils would be and after several hours of google searching I was none the wiser the largest contactor I plan to use is 65 amp 4 pole with a 240v coil (in Australia we run 240v single phase or 415 3phase).
Does anyone know how many amps these coils draw or the min rating for the control switches?

Feel your pain on lean supply channels. But an RPC panel need not look like anything "special", artistically.

Just over-kill it, say 5, 10, or 15 A?

See what's on the local shelves for controlling light to medium loads, directly.

Stock goods, similar to Aus-made goods I've used in HKG.

- ON/OFF to switch as much as 3 & 6 KVA instantaneous water heaters, specific-purpose appliance outlets, HVAC, and small kitchen ovens.

- MOMENTARY as used for a powered door or a pump.

Contactor coil or relay coil load will be much less!

dalmatiangirl61 · Sep 28, 2020

I seem to recall trying to figure out how much current the coils draw a few years ago, it was explained to me that it only draws a few amps in the second it engages, once fully engaged it drops to milliamps.

JST · Sep 28, 2020

The coils should have a VA rating. That translates to current (divide by volts).

The switches may have a VA rating also. It should be at least the coil rating. IEC switches will also have a type of load rating, but any control switch should be rated for inductive.

This is for AC coils. DC is different, it's just current, and an inductive load, but the switch needs to be good for DC.

SomeoneSomewhere · Sep 29, 2020

You have a few options in Australia that should be off the shelf:

One or more press mechs (there may also be push button versions) in a standard light switch plate.

22mm push buttons and contact blocks.

These are Schneider list prices, also known as one of the world's best works of fiction, and other manufacturers and other series are also available and probably cheaper.

Krankieone · Sep 29, 2020

thankyou but at around $100 for a pushbutton and contact I may be in for a long wait for something cheaper I need 6 I think I may need to chat with the sparky at work or order from overseas if that doesnt work

SomeoneSomewhere · Sep 29, 2020

As I said, the list prices are a work of fiction.

I went for Schneider because their website is easy. Walk into a wholesaler and ask them what's cheap.

Your other option is to try and find an industrial scrapper/used parts seller. I imagine they'll have a few old control cabinets that you can pinch buttons out of for $5 each.

Hopefuldave · Oct 3, 2020

SomeoneSomewhere said:
As I said, the list prices are a work of fiction.

I went for Schneider because their website is easy. Walk into a wholesaler and ask them what's cheap.

Your other option is to try and find an industrial scrapper/used parts seller. I imagine they'll have a few old control cabinets that you can pinch buttons out of for $5 each.

EvilBay will have *cheap* buttons, I used them in my RPC and haven't had any problems in the yeear or two it's been running - they have natty dual red/green (NC/NO) with an amber lamp between, separately wired from the switches, look good (apart from the lopsided I O labelling) and work well enough for contactor coil currents.

Dave H. (the other one)

thermite · Oct 3, 2020

Hopefuldave said:
EvilBay will have *cheap* buttons,

eBay, Mouser, others. ALSO have now and then as "NOS" or "NNB" the "remaindered" SKU from the major-makers.

If. for example, A-B made a button-switch for 10, 20, or 40-odd years, then changed materials and method of assembly, a new SKU was assigned.

Technically, the last (decade? scores of years? ) item is obsolete and orphaned.
Needless to say, they WORK as well as they ever did.

So no, "cheap Chinese' is not the only option. Even a USED top-tier maker's switch, cleaned-up, might be the better deal.

Depends on what sort of service it saw. Lot's of them just SIT, very few cycles in very long years.

SomeoneSomewhere · Oct 3, 2020

OP is after quick shipping; ebay unfortunately is not generally that.

thermite · Oct 4, 2020

SomeoneSomewhere said:
OP is after quick shipping; ebay unfortunately is not generally that.

Not to NZ, I wuddn' think. Otherwise, depends on the vendor. NRi, Mouser, et al, I use THEIR website to order anyway. Same again several circuit breaker and other NEMA switchgear goods vendors with ebay stores "also" or never did have.

Digi-Key I've been using since their first or second year of existence, Newark as Beltway-bandit DoD contractor even longer, so ePrey has never entered at all.

Krankieone · Oct 6, 2020

I received the contactors and fortunately the supplier sent a catalog with some fairly smart looking push button switches @ $8 and change and they have good prices on switched 3 phase 5 pin sockets for other Aussies the web page is nixson-dce.com losasso.com — Servers

thermite · Oct 7, 2020

Krankieone said:
I received the contactors and fortunately the supplier sent a catalog with some fairly smart looking push button switches @ $8 and change and they have good prices on switched 3 phase 5 pin sockets for other Aussies the web page is nixson-dce.com losasso.com — Servers

Broken. Says no such domain. Even if I cut and paste the text, rather than the link.

You need to edit it to start "https" rather than "http"

That finds it open on the secure httpd port.

Krankieone · Oct 16, 2020

Nixon Data Comms & Electrical | ONLINE ELECTRICAL WHOLESALER

Krankieone · Oct 16, 2020

thermite said:
Broken. Says no such domain. Even if I cut and paste the text, rather than the link.

You need to edit it to start "https" rather than "http"

That finds it open on the secure httpd port.

Thankyou for pointing that out my lack of computer skills is showing again I hadn't noticed there was more than one prefix for web addresses.

With the Covid delays the switches turned up 10Amp rated each with a normally open and normally closed contact
,still waiting on the cable out of Sydney.

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