A question for the three phaseists

[8ob]

My tyre changer which is three phase has started to knock out the trip, checked out the lead/plug and and all the obvious. Noticed with the side cover off the motor will nudge about quarter of a turn before the trip goes.

Is there a simple way of eliminating the switch from the motor? The switch is a foot operated forward and reverse, it will trip either way I try and run it.

 

[Pete.]

I would just remove the terminal box cover on the motor and pull the three wires. Make sure they aren't touching anything (or each other) and try the pedal. That'll pin-point the fault at least.

 

[EM1L4]

Is it tripping the MCB or the RCD? If it’s the MCB the. This might be a faulty motor (or internal wiring) if it’s the RCD then it can be anything from damp cobwebs (yes this is a thing!!) to broken insulation...

 

[123hotchef]

Is it tripping the MCB or the RCD? If it’s the MCB the. This might be a faulty motor (or internal wiring) if it’s the RCD then it can be anything from damp cobwebs (yes this is a thing!!) to broken insulation...

oh man damp cobwebs in boxes are the vain of my life!

 

[EM1L4]

oh man damp cobwebs in boxes are the vain of my life!

Lol you’ll only ever know that with experience, I don’t recall it being taught in any electrical classes I attended! The first time took me a while, couldn’t quite believe it...

 

[123hotchef]

Lol you’ll only ever know that with experience, I don’t recall it being taught in any electrical classes I attended! The first time took me a while, couldn’t quite believe it...

they didnt have RCDs back then! quick clean out spray of contact cleaner £50 later on your way! well if you can find the cobweb quick

 

[EM1L4]

they didnt have RCDs back then! quick clean out spray of contact cleaner £50 later on your way! well if you can find the cobweb quick

I do event electrics on the side, the weirdest one (apart from damp cobwebs inside a catering urn) was those fancy “vintage” light bulbs, turns out the super warm colour came from a metallic colour on the side of the lamp glass, (I had a large circuit trip, eventually narrowed it down to the lamps above the bar),which was earthed via the BC lamp holder, when the lamp blew the filament made contact with the glass and metallic colour tripping the RCD (not MCB) took me a while to figure that out!

 

[arther dailey]

common thing with one firm was mice, they would get in the vents of the bigger electric motors and for what ever reason knaw on the varnish , next morning switch on and bang..

 

[brightspark]

worst one i went to was a cooker tripping . pulled it out and it stunk took the back off and there was a dead mouse festering its nose and front paws were touching the earth and its ass was stuck on the live terminal

 

[brightspark]

is it the mcb or rcd tripping

 

[8ob]

Got Ed to check out the motor and he said it was plucked or something like it, he is welsh and I didn't believe him so I took a peep inside.

He was right

Ordered and fitted a replacement off the bay of thieves.

And the old motor will be winging its way back to China very shortly

 

[Turbo]

And the old motor will be winging its way back to China very shortly

Do you not separate your scrap out? While old motors are not as valuable as copper wire they are worth many times more than general scrap!

 

[My Old Landy]

Scrap bin? I only saw a spare parts and save for later bin

 

[8ob]

Do you not separate your scrap out? While old motors are not as valuable as copper wire they are worth many times more than general scrap!

I will if it’s an easy separation but really can’t be bothered with things like motors, I do keep Ali separated out because I intend to smelt some for castings in the near future.

Bob

 

[sako243]

He was right

Usually am

 

[500e]

Had mice gnawing through alloy Caps on one remote radio site in the middle of a wheat field why our kit

 

[8ob]

Another question

I have two vac motors for a flow bench that both draw 5.5kw each, I need one to run at full speed and the other to run through a motor speed controller. Is it better to get a 12kw starter to fire up both at the same time and fit a speed controller to one of them or split them up?

 

[Dave-sparks]

A starter for each motor, as the starter usually incorporates the overload protection.
The overload protection needs to be set to the exact requirements of each motor otherwise it won't protect the motor.

 

[Screwdriver]

Lots of copper in those motors and you can smelt that just as easily.

 

[MCKDAVID]

just seen this and from your other thread, 5.5kW x 2, how much pressure do you need? the flow rate of two of these will be fairly high I'd guess but to need 2 x 5.5kW that's going to be a powerful heavy duty bench .

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