Contactor question

[Leejohnson222]

I need to replace a standard contactor 25a
That is used to pull in a 3 phase extraction fan.
I called a wholesaler who said just put a 63a one in it will be fine.
Surely I would be in danger of over current with this ?

I've not used many contactors so want to make sure it's installed correctly. I usually prefer to change like for like.

 

[westward10]

25A is just the current capability of the contacts. The current draw is dictated by the fan not the contactor rating. Does the existing one have an overcurrent relay fitted.

 

[Pete999]

I need to replace a standard contactor 25a
That is used to pull in a 3 phase extraction fan.
I called a wholesaler who said just put a 63a one in it will be fine.
Surely I would be in danger of over current with this ?

I've not used many contactors so want to make sure it's installed correctly. I usually prefer to change like for like.

How is the fan started DOL. S.D, ??

 

[Leejohnson222]

Its DOL and has some speed control, the contactor has a built in reset almost like a rcd that the user can reset on the front

 

[James]

if this is in an enclosure with a start and stop/reset button on the front then,
change like for like, any change in the physical size will stop the buttons from working.

 

[ipf]

As long as the contactor will fit and has the current carrying capacity, it's the overload size that matters. The 'built in reset' is not an rcd, probably the overload. You say the user can reset it......is it in a control panel or a stand alone starter

 

[James]

I am presuming it is in a box like this?
if so, the same make and model is important.
p.s. there are 2 items in there, the contactor is the bit at the top with white label showing and the overload is the bit at the bottom with a small red button.

 

[ipf]

I am presuming it is in a box like this?
if so, the same make and model is important.
p.s. there are 2 items in there, the contactor is the bit at the top with white label showing and the overload is the bit at the bottom with a small red button.
View attachment 53819

Maybe. But where is the 'reset on the front'?
If that's what it is, it may be as per the photo but inside a panel.
I'm not PRESUMING, though. Let's wait for further info.

 

[Leejohnson222]

Maybe. But where is the 'reset on the front'?
If that's what it is, it may be as per the photo but inside a panel.
I'm not PRESUMING, though. Let's wait for further info.

No there is a controller that has on and off and under that controller is a contactor that is inside an enclosure but has a reset connected to a coil.

 

[westward10]

Some pics of the internal parts would help.

 

[ipf]

No there is a controller that has on and off and under that controller is a contactor that is inside an enclosure but has a reset connected to a coil.

In that case, it’s not on the front, it’s in an enclosure. If it needs to be regularly reset, it may be a motor or contact problem and shouldn’t be interfered with, especially by someone unqualified, working in situ.

 

[Leejohnson222]

In that case, it’s not on the front, it’s in an enclosure. If it needs to be regularly reset, it may be a motor or contact problem and shouldn’t be interfered with, especially by someone unqualified, working in situ.

I'm qualified but not seen anything like this before. Contactor connections are inside an enclosure and reset sit in a cut out for end user reset

 

[westward10]

That is a motor protection circuit breaker. What is wrong with it.

 

[SheffSimon]

As above, it's an MPU.

OP - if you don't understand that, maybe time to tell your customer the same.

 

[Leejohnson222]

As above, it's an MPU.

OP - if you don't understand that, maybe time to tell your customer the same.

Well I was asking here as I wanted to changed like for like but the wholesaler had no idea what it was from the model number
[automerge]1575048486[/automerge]

Well I was asking here as I wanted to changed like for like but the wholesaler had no idea what it was from the model number

I love the welcoming overwhelming support you get here, like there aren't so many different types of electricians and if you ask a question or for help your told to get a professional, wonderful