# Contactor question..



## kevmanTA (Jul 20, 2010)

Today, was looking for a interlocking 600V set of contactors with a 24V DC coil..
It was for a Wye-Delta starter on a band saw, big bugger..
Went to the whole saler nearest to the job, guy tries selling me an interlocking contactor with a 24V 50/60 hertz coil..
Tried explaining the difference, he just kept saying it's the same thing..

So, was I right that if you used a 24V 50/60 hertz coil contactor in the place of a 24V DC one, you would have some problems?


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## MDShunk (Jan 7, 2007)

Never tried it, but my gut tells me it either wont work or it will sing to you if it does.


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## kevmanTA (Jul 20, 2010)

Sing or burn up, I once removed a diode wired in series to a 24V solonoid, what a sound..


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## frenchelectrican (Mar 15, 2007)

kevmanTA said:


> Today, was looking for a interlocking 600V set of contactors with a 24V DC coil..
> It was for a Wye-Delta starter on a band saw, big bugger..
> Went to the whole saler nearest to the job, guy tries selling me an interlocking contactor with a 24V 50/60 hertz coil..
> Tried explaining the difference, he just kept saying it's the same thing..
> ...


In some degree you will run some problems especally if the whole control circuit is wired for DC instead of AC and with AC coil on DC soure it may not operating properly or drop out but some contractor they use DC coil due the noise or chatter that can affect the performace on the concats or motour operation.

Merci,
Marc


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## oliquir (Jan 13, 2011)

coil will burn, ac coil has very low resistance when use in DC, you could use a 48vac to equal approx a 24vdc coil

for example i have 2 small relay (identical shape) one at 24vdc has a 1kohm resistance and the 24vac has below 250 ohm

the 24vdc one will dissipate 0,5W and the 24vac will dissipate 2,3W


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## guest (Feb 21, 2009)

kevmanTA said:


> Today, was looking for a interlocking 600V set of contactors with a 24V DC coil..
> It was for a Wye-Delta starter on a band saw, big bugger..
> Went to the whole saler nearest to the job, guy tries selling me an interlocking contactor with a 24V 50/60 hertz coil..
> Tried explaining the difference, he just kept saying it's the same thing..
> ...


Kevin, depending on manufacturer, you could possibly order a set of contactors with replaceable coils and get the 24vdc coils as a replacement. Had to do that once on a rectifier, ordered a 240vac coil contactor (was the only contact configuration/form that would work) and the replacement coil at 120vac to make the one I needed.


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## MDShunk (Jan 7, 2007)

mxslick said:


> Kevin, depending on manufacturer, you could possibly order a set of contactors with replaceable coils and get the 24vdc coils as a replacement. Had to do that once on a rectifier, ordered a 240vac coil contactor (was the only contact configuration/form that would work) and the replacement coil at 120vac to make the one I needed.


I've had to do that quite often. Buy whatever starter or contactor configuration is "stock", and get the replacement coil for the voltage you need. Some supply houses will swap out the coil for you, order a new starter with the right coil, and swap things back on their end and put them back in stock so you're not stuck with parts you don't need.


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