If a relay is rated 120vac 10 A can I use it for less amperes at 230v ?

[thebadtall]

Hello, I was looking for relays.

if a relay is rated 120vac 10 A can I use it for less amperes at 230v ?
thank you

 

[mailus]

Re: overvoltaging a relay

yes, you can use it. But current rating is half of the original rating.

 

[FboDigit]

Re: overvoltaging a relay

No you can't the coil is made for a specific voltage and you will simply make the coil spark internally. That will break your relay permanently.

 

[thebadtall]

Re: overvoltaging a relay

:/ very sad and i have found very cheap 120v relays...

 

[mailus]

Re: overvoltaging a relay

He is asking for relay contact not for coil. May I correct?

 

[thebadtall]

Re: overvoltaging a relay

yes, the coil control voltage is 12v , i want to know if i can pass a 230v voltage of 500ma through it

 

[mailus]

Re: overvoltaging a relay

yes,you can use it without any problem Upto 5A.

- - - Updated - - -

For more reference check this link...
www.exman.com/relay.html

 

[FboDigit]

Re: overvoltaging a relay

I hope your relay is cheap because I really think that if you put 230V ac on a coil rated 120Vac you will completly destroy it.
Even if it support the current, the voltage is to high. The voltage will make the spire to short circuit.

The same thing apply to a transformer.

 

[mailus]

Re: overvoltaging a relay

His specification:
coil voltage 12v DC.
Relay Contact rating 120v 10A AC.
He is asking about relay contact.
It can able to switch 230v 5A AC supply.


Pls ask your question clearly...

 

[FboDigit]

Re: overvoltaging a relay

His specification:
coil voltage 12v DC.
Relay Contact rating 120v 10A AC.
He is asking about relay contact.
It can able to switch 230v 5A AC supply.


Pls ask your question clearly...

It is not better on the contact, when the contact is ON there is no problem but when you switch OFF then there is a possibility that the voltage is to high and a spark can happen between both side of the contact

 

[FvM]

Re: overvoltaging a relay

there is a possibility

I agree that you are possibly able to find a few relays on the market that are rated for 115 VAC but not for 230 VAC. They are mostly "signal" relays with 1 or 2 A current rating. I'm not aware of a 10 A type that switches 115 VAC and can't stand 230.

But to be sure, you'll want to consult the data sheet.

 

[mailus]

Re: overvoltaging a relay

As per relays contact rating 120V 10A so it can capable to switch 1200VA. If you reduce the current and increase the voltage that is 230V 5A this also 1150 with in the limit of 1200 VA. So there is no doubt you can use it for upto 5A. If you have any doubt search for data sheet....

 

[FvM]

Re: overvoltaging a relay

After some searching, I found a 120 VAC relays that is not explicitely rated for 230V in the datasheet. The contacts are still specified with 750 VAC dielectrical strength, and if you look on the relay photo...

https://www.nteinc.com/relay_web/pdf/R46.pdf

 

[tpetar]

Re: overvoltaging a relay

As per relays contact rating 120V 10A so it can capable to switch 1200VA. If you reduce the current and increase the voltage that is 230V 5A this also 1150 with in the limit of 1200 VA. So there is no doubt you can use it for upto 5A. If you have any doubt search for data sheet....

You cant use relay against manufacturer datasheet data - electrical characteristics. Voltage of 220V is twice as 110V, and this cant be compensated just with lowering of current. Also DC AC current..... I'm always for usage with declared load. Save this relays for some other projects, and buy new with adequate characteristics.

 

[Raza]

Re: overvoltaging a relay

Hello, I was looking for relays.

if a relay is rated 120vac 10 A can I use it for less amperes at 230v ?
thank you

You can use the relay to any current less than rated contact, but if the contact voltage is increased the FLASH on the contact while it is breaking will increase (specially on Inductive loads) hence damaging the contact more rapidly as specified in the manufacturer's datasheet.

 

[thebadtall]

Re: overvoltaging a relay

hello again ! please, dont fight
The particular relay i was asking about, i saw datasheet, it supports 250V at half amperes !!
Thank you !!

 

[FvM]

Re: overvoltaging a relay

it supports 250V at half amperes !!

Sounds like a DC specification.

 

[tpetar]

Re: overvoltaging a relay

I think that is better to buy new relay with clear data specification for your need. There is low cost relay in shops, and its better to get adequate part, than that obtain melting or even fire. Specially if realy should switch some heater or device without your attention, when you are absent from that location.

Also I think that is no good to force relay contacts to work on their limits or over that, that can cause bad situations.

On this location you can see how relay welded contacts looks like, and contacts properties :

https://electrical-engineering-portal.com/properties-of-relay-contact-system

 

[thebadtall]

Re: overvoltaging a relay

ok thank you for information
i have another question
what about another relay, wich is rated for 6vDC and i supply it with 5vdc from usb port, will it swich on ?

 

[tpetar]

Re: overvoltaging a relay

I think it will work. Always try to use declared voltage for relay coil, because this coil must have power to disconnect contacts, if power is insufficient maybe there is chance that contact cant separate due higher currents.

When buying relays always look to buy thise with higher coil winding resistance, this will consume smaller ammount of current in circuit.