I have a Unite my1018z 450 watt motor. I've been running it at 50V :? It died today. I am not sure what caused it, but what happened was I was happily riding along when suddenly I noticed the power cut out completely briefly. Then, when it returned, it was about 25% reduced. Also, the motor "exhaust" from my cooling fan was very warm despite just having begun my ride. There was a lot of motor resistance even when I just let the bike roll.
Upon opening up the motor, I noticed one part of the winding was much darker than the others, and there was a white powdery residue near the charred area of the winding. The kind you see when you vaporize pieces of metal with a high current arc. (I used to see this when I melted my connectors connecting them in reverse polarity)
Also, I noticed a tiny strand of metal from some stranded wire I had been using, near the "intake" side of my motor cooling. I theorize some of this stranded wire got sucked into the motor, and eventually found an exposed area of the winding to contact and make sweet short circuit love with.
My motor's windings have always confused me a little. I had always thought that the entire winding was a single piece of wire. Yet, I had noticed before that it was broken in one place. It still worked fine, so I never worried about it too much. Is it possible that my motor used several windings in parallel? Why would they do that, instead of just using fatter wire? And, is this even possible or likely?
In any case, I've wanted to rewind the motor for some time and this gives me the perfect oppourtunity. I've already eagerly torn off the old windings, and am set to begin except for a few small things. One, I have no magnet wire. Two, I don't know how to do the pattern. I have read through a rewinding guide for the 250W motor here: http://www.scootersupport.com/motorrewind.htm but it is a little different. He says the winding pattern is very simple, and you use a single piece of wire. How to proceed? I want to use a pattern or number of turns which will work well with 55.5V and a 15:1 gear ratio, on a 26'' wheel. How do I figure out how many turns to use, and should I use a single wire?
The original motor specs are: my1018 450W 24V, 2.5A no load current, 4600 rpm, 4000 rpm loaded @ 25A.
So, I guess that means it is a 192 rpm/V motor?
Also, for the magnet wire, I can order it from ebay here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180499236413 or I might be able to get some from a local Radio Shack or electronics store. I am thinking its a little silly to pay $25 for new wire, when the original motor only cost $45. For the magnet wire, I read it is important what kind of enamel is on it. The ebay stuff says its good up to 200C. I doubt my motor windings have ever gotten above 50C, based on the "exhaust" temperature. If I get higher temp enamel, does this reduce the performance of the motor?
I think that is all for now...
Upon opening up the motor, I noticed one part of the winding was much darker than the others, and there was a white powdery residue near the charred area of the winding. The kind you see when you vaporize pieces of metal with a high current arc. (I used to see this when I melted my connectors connecting them in reverse polarity)
Also, I noticed a tiny strand of metal from some stranded wire I had been using, near the "intake" side of my motor cooling. I theorize some of this stranded wire got sucked into the motor, and eventually found an exposed area of the winding to contact and make sweet short circuit love with.
My motor's windings have always confused me a little. I had always thought that the entire winding was a single piece of wire. Yet, I had noticed before that it was broken in one place. It still worked fine, so I never worried about it too much. Is it possible that my motor used several windings in parallel? Why would they do that, instead of just using fatter wire? And, is this even possible or likely?
In any case, I've wanted to rewind the motor for some time and this gives me the perfect oppourtunity. I've already eagerly torn off the old windings, and am set to begin except for a few small things. One, I have no magnet wire. Two, I don't know how to do the pattern. I have read through a rewinding guide for the 250W motor here: http://www.scootersupport.com/motorrewind.htm but it is a little different. He says the winding pattern is very simple, and you use a single piece of wire. How to proceed? I want to use a pattern or number of turns which will work well with 55.5V and a 15:1 gear ratio, on a 26'' wheel. How do I figure out how many turns to use, and should I use a single wire?
The original motor specs are: my1018 450W 24V, 2.5A no load current, 4600 rpm, 4000 rpm loaded @ 25A.
So, I guess that means it is a 192 rpm/V motor?
Also, for the magnet wire, I can order it from ebay here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180499236413 or I might be able to get some from a local Radio Shack or electronics store. I am thinking its a little silly to pay $25 for new wire, when the original motor only cost $45. For the magnet wire, I read it is important what kind of enamel is on it. The ebay stuff says its good up to 200C. I doubt my motor windings have ever gotten above 50C, based on the "exhaust" temperature. If I get higher temp enamel, does this reduce the performance of the motor?
I think that is all for now...
.
