[Russ Chadd]

I was using my Ashby's spotter today and all of a sudden the motor lost power and an electrical burning smell was detected, i can only assume that the motor is knackered and needs replacing.

Here is the model : Ametek 2 Stage Bypass 4.8" 240v 750 117304-50

Where would be the cheapest place to purchase this motor?

Cheers

Russ

[venom]

have you checked the carbon brushes

[Russ Chadd]

To be honest no... does this sound like it could be the brushes? in the past when the carbon brushes are wearing, motors lose power granularly... this lost nearly all its power and the smell of burning was strong... 

[venom]

To be honest no... does this sound like it could be the brushes? in the past when the carbon brushes are wearing, motors lose power granularly... this lost nearly all its power and the smell of burning was strong... 

i have had them go both ways worth checking only take a few mins and around £7

[Russ Chadd]

Stupid question... how would i be able to detect if they are knackered?

[Kinver_Clean]

The symptoms you describe a classic motor burnout.
Finis.

[venom]

there will be 2 screws holding them in if they are worn there will be no carbon just a little bitnew ones look like this

http://compare.ebay.co.uk/like/310297155896?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&adtype=pla&crdt=0

do it a bit like this
http://www.youtube.com/watch?v=SsfsSIbWYaI

[venom]

The symptoms you describe a classic motor burnout.
Finis.

it might be but worth checking the brushes just in case

[Russ Chadd]

Thanks guys, just had it running with the bottom off and its sparking like a good'n, there appears to be a little corrosion around one side of the motor which suggests it has become damp, will have a look at the brushes... thanks for your kind help

[Russ Chadd]

Carbon brushes look like they have plenty of life left, however there appears to be a constant blue "ark" coming from the part where the brushes make contact and after 20 or so seconds the circuit breaker cuts out... any ideas?

[Kinver_Clean]

Does the commutator ( the bit the brushes run on) look rough and black? It should be a darkish colour but smooth and almost shiney.
Are the sparks about 1/4" long?
Does the motor make a humming rumbling sort of noise like its got a sore throat?

If so bin it.

[Russ Chadd]

The commutator looks ok, no signs of burning out and the motor spins freely when the brushes are removed,
When its running it has a rumbling sound where its arking, tried removing the brushes and cleaning the end but this hasnt helped... also cleaned up the commutator using some very fine wire wool to removed any contamination.

The trouble is i could pay £20 for new brushes and if thats not the problem then its a new motor i guess... any thoughts?

[seamus campbell]

Hi Russ

That seems to be the same case with my motor arcing on one brush  and rumbles when brushes on  can i ask how old is you machine and does it get much use

[Russ Chadd]

Well its in really good condition, pump and heater all work great... i did however notice some possible water contamination to the chassis of the motor which suggests that in its past life it may of got wet or damp... whether this has anything to do with the problem i dont know...?
I did check for leaks however everything seems to be fine 

[dan paton]

sorry to butt in on the thread but at the moment there's nothing wrong with the motors in my machine but i don't want it breaking down on me . if i change the brushes will this prolong the life of the motors
                                dan

[Neil Jones]

yes it will Dan