The Shop > Tools
micro mill electricals problems, help please!!
steampunkpete:
Or possibly sticky brush(es).
f you live anywhere near St. Albans and could drop the motor off, I could give it a going over for you (within the limitations of the equipment I have). In the far distant past I did some design work on PM brushed motors, some with (what were then) exotic magnetic materials.
I did notice the unusual label on one of the lamps on the control box - "unnormal".
BaronJ:
Hi Paul,
Sorry to learn the sad news. :hammer: :hammer: :hammer:
I wonder did you do the insulation of the motor windings to case check as I suggested ? You never said.
Bluechip:
Metering/ Meggering to deck may not show the fault if it is an inter-winding fault.
My WM16 motor went pop about 18months ago and meggering from a brush to the casing while turning by hand showed nowt at all ... :thumbup: but ......
Stuck it on my Variac via a bridge rectifier and it was fine until some 40V r.m.s. then the arcs tracked around the commutator ... amusingly :zap: but not helpful. If I let it cool off for a bit it would run for several minutes OK below the 40V mark. New motor fixed machine, it didn't kill the KB board ( the thyristor version).
Maybe some winding had chafed in the slot and was shorting to adjacent turns ??? Hoo nose ???
Commiserations to Paul .. :(
Dave
pmdevlin:
ok all,
just so I have not mislead you, the sparking wasn't/isn't constant, it was more a flash as the first fuse blew. Motor was stone cold, brushes are perfect.
Bluechip, thanks for input but have no idea what you are talking about, remember, I am thick!
Baron, same sorry, I thought you guys might get fed up of me! so didn't reply due to embarrassment :doh:
Pete, many thanks for very kind offer, but I am Wirral, so miles away
John, I will try to get back to what you had, can you please post an ebay link for the right fet, I had a quick look, and there seem to be different specs for that part number. Ill get a pot from arc euro also, for that price it is worth it, then if all agree its the right course of action, at least get back to a proportional bulb as John had it. If I have a spare fet, then I can try on the motor, if it blows again, change the fet again, and with a new pot it must be the motor?
I would have thought the motor would give a clue, such as smell of electrical death, burning, burnt wires etc. As the motor could have been the original fault, I have no way of going back to our "expert", he had it running for a while on 60vdc, I take it when it starts to get up to 230vdc that is when things go wrong!
Paul
Is there a very simple test I can do on the comm, such as a test light on each segment to establish anything worthwhile!
lordedmond:
Paul yes there is a test
It's simple when you have the required DC source it's called a volt drop test but that motor has a thick winding in relation to its size you would need to measure about 0.1 volts and a current limited 2 volt source
Stuart
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