LumberJocks

3 phase contactor, what am I looking at?

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Loren posted 71 days ago 375 views 0 times favorited 7 replies Add to Favorites Watch
View Loren's profile

Loren

6761 posts in 2149 days


71 days ago

Here are some not very good pictures of a toasted magnetic contactor. It’s an S-C35L. It’s a 35 amp 3 phase contactor from Asia. It’s probably about 25 years old. It looks to me like the basic contactor is stacked on another thing, a base, which I think functions to provide 110v power to a pneumatic solenoid valve. It’s from a 13” wide belt sander made by JET. The machine is old enough that there’s no manual available on the JET site. I haven’t called JET, but in any case I have doubts as to whether they’d have this part. The contactor doesn’t work very well starting the motor but will do so. The contacts are in bad condition so it chatters sometimes. The other problem is when the air is hooked up, the contactor chatters on and off and this turns the solenoid on and off which pulses the pneumatic brake cylinder and works against the motor getting started.

It need replacing in any case. I think what I need is just the top part, but I need one that is compatible with the 110v base part. So it’s a spec and mounting issue. I’ve taken it apart and examined everything. The coils inside look good. Only the contacts are bad.

I don’t want to spend a lot of money replacing this part on a machine that may have other problems, so I’m looking for the least costly short term way to get this working so I can further assess the status of the machine.

I appreciate any insight on repairing or replacing the top part of this sort of stacked unit.


7 replies so far

View bigblockyeti's profile

bigblockyeti

929 posts in 222 days


#1 posted 71 days ago

While contactors can be disassembled, I have never seen where only part of one can be purchase except for one being fixed in the steel mill I used to work that carried up to 5000 amps at 480V (it was big). While they can be had used for little money, most are reluctant to sell them for liability reasons, making it a buyer beware market.

View Loren's profile

Loren

6761 posts in 2149 days


#2 posted 71 days ago

I think what I’m looking at is a 110v coil in there that
is actually not affected by the contactor at all. I’ll need
another contactor that is designed to accept one of
these internal 110v coils. Or I could just install the coil
outside the new contactor.

View bigblockyeti's profile

bigblockyeti

929 posts in 222 days


#3 posted 71 days ago

If you could by chance find the exact or very, very close to the same contactor that I see no reason why you couldn’t use your good coil with a set contacts that are in serviceable condition.

View crank49's profile

crank49

3245 posts in 1473 days


#4 posted 71 days ago

All the magnetic contactors I ever saw had a coil, sometimes 110V or 24V. The coil is an electromagnet that pulls the contacts together when energized. If your coil is working, and it sounds like it is, perhaps you can dress the contacts enough to get them working.
There are sometimes auxiliary contacts that are in the circuit to create what is called a holding circuit. Sometimes these contacts are used for other things like an extra load.
That old stuff was usually made in such a way you could get the contacts out to dress them with a file.
Modern starters are made to just self destruct so you have to replace them when they malfunction.

-- Michael :-{| Diapers and politicians both need to be changed often; and for the same reason.

View Loren's profile

Loren

6761 posts in 2149 days


#5 posted 71 days ago

The contacts are wrecked beyond filling.

I ordered a Toshiba contactor in the same general format.
Maybe I’ll switch out the contacts if they are the same style.

View TopamaxSurvivor's profile

TopamaxSurvivor

14402 posts in 2177 days


#6 posted 71 days ago

If it is chattering, it is probably contamination on the magnetic pole faces, not the contracts. If you can still get pats for that model, you could possibly fix it. It is generic part. Anyone with the same electrical characteristics should work just fine.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View TopamaxSurvivor's profile

TopamaxSurvivor

14402 posts in 2177 days


#7 posted 71 days ago

BTW, use emery cloth to clean the pole faces. Normally, the contacts are just fine unless they are totally burned away. The pitting and silver oxide that builds up is part of normal operation.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase