Electric motor checks by enthusiastic amatuer

Greetings,

I have to lay this out in best typing as I'm not allowed to post pictures, yet.

A friend has a sick electric/hydraulic log splitter. I fixed a hydraulic fault some time ago but now the motor is seized.

I'm mechanical by trade with some electrical experience from my time at sea.

The  motor is 230v, 13.2A, 50hz, P1 3.00kW, P2 2.35 kW, 2,800 RPM, S6 40%, Cos 0.37, IP 54, Isol. KI B, VDE 0530/11.72

All the above from motor ID plate.

The chopper was working away when the circuit breaker tripped, the owner saw smoke coming out of the plug/socket on the machine. 

I dismantled this and the female connectors, (on the plug end) were burned badly. It's a German type F plug and I fitted a new one.

On trying to start the machine, nothing happened. I took the motor fan cover off and it's seized.

Today I measure resistance at the three wires coming from the motor, (all disconnected).

There is one wire lighter than the other two, I presume the 'common'.

I got 330 ohms between both heavier wires to the common.

0.003K ohms between both heavier wires.

All wires to motor casing zero ohms.

Motor is aluminium with cast iron ends.

So, what say ye?

Zero ohms from winding to earth means it is knacked.

Is one of the Chinese ones from eBay, I got one once brand new and when I opened up the plug top on it I found it was shorted out with a bit of wire, as the starting current would blow the fuse, naughty naughty Chinese man.

roys said:

Zero ohms from winding to earth means it is knacked.

Is one of the Chinese ones from eBay, I got one once brand new and when I opened up the plug top on it I found it was shorted out with a bit of wire, as the starting current would blow the fuse, naughty naughty Chinese man.

Click to expand...

Thanks Roy,

Does this mean the seizure is due to rotor contacting stator?

The machine is pretty old. Young woman owner used it for winter income years ago supplying split logs. 

Recon motors still make it an iffy repair. I think new splitters come in around £400.

?  https://www.google.co.uk/search?q=log+splitters&client=safari&hl=en-gb&prmd=svin&source=lnms&tbm=shop&sa=X&ved=0ahUKEwiGqN_3xpnZAhXKZlAKHSmFCGQQ_AUIESgB&biw=375&bih=553     ??

Sharpend said:

?  https://www.google.co.uk/search?q=log+splitters&client=safari&hl=en-gb&prmd=svin&source=lnms&tbm=shop&sa=X&ved=0ahUKEwiGqN_3xpnZAhXKZlAKHSmFCGQQ_AUIESgB&biw=375&bih=553     ??

Click to expand...

Among these is the Woodstar type she has. A vertical 6-7 tonne machine. Her requirements now are only for her own use so a small one should do, although she has access to fallen timber locally.

It's a sentimental problem, the old machine has done her proud, for her it's cruelty to give up on it.

I'm going to suggest a new one and a kitten.

Clutha said:

I opened up the plug top on it I found it was shorted out with a bit of wire, as the starting current would blow the fuse, naughty naughty Chinese man.

Click to expand...

I've seen a Chinese IEC lead with moulded on connectors where the 13amp plug had no provision for a fuse. That would have solved the start current problem!

Clutha said:

Among these is the Woodstar type she has. A vertical 6-7 tonne machine. Her requirements now are only for her own use so a small one should do, although she has access to fallen timber locally.

It's a sentimental problem, the old machine has done her proud, for her it's cruelty to give up on it.

I'm going to suggest a new one and a kitten.

Click to expand...

She must have the patience of a saint using these splitters, they look very similar to the Chinese one I bought of eBay, they split wood, to me, at a very slow pace, I find I am quicker using a splitting maul. I only use this type of eltro hydraulic splitter once a year on the saved up very knarwly logs that human and splitting maul just bounce off.

In answer to your question about seizure it could be due to a few issues:

Hi load, with no overload protection causing a locked rotor causies winding failure.

Bearing failure, with no Overload protection etc. Etc. As above.

Poor winding quality insulation and it just had a melt down.

Water ingress causing insulation breakdown.

There can be other causes but I reckon one of these four will be most likely.

roys, 

I think your water ingress leading to insulation breakdown would be my no.1 .

She had domestic issues some time ago and all her landscape gardening equipment, (her summer work, self employed) and the splitter were stored with a friend, but not under shelter as she thought, everything left outside in the weather.

She's now settled in her own place (her DIY skills in the 1860's house are amazing). After fitting her solid fuel stove she tried getting the chopper working again. Hydraulic valves had stuck and I got that sorted and the machine has been used quite a bit since.

I think the insulation has now given up, but will pull the motor off and confirm.

Thanks everyone for the great response to my query.