# Mars ME 0709 problem.



## major (Apr 4, 2008)

Duxuk said:


> At 40mph on a level surface I am confident that my motor would draw about 85 amps at 48 volts.


Hi Andrew,

It sounds like you really don't know what current it draws, do you? I suspect you have overloaded the motor. After you get it repaired, you had best put an ammeter in the motor circuit.

Regards,

major


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## frodus (Apr 12, 2008)

What is your gear ratio?

Are you measuring amps on the motor side? or the battery side? There's a HUGE difference..... you could only be drawing 100A on the battery and put out well over 300A on the motor side. You should measure with a clampmeter on the motor side.... set to PEAK/HOLD on the ammeter.

Thats a lot of weight for a single Mars motor....almost 900lbs (~730 of that being the bike)..... thats got to be one of the heaviest vehicles I've ever heard of with one single mars motor. Even under 45, that thing has to draw a ton of amps to push that vehicle.

I don't suspect you overloaded it, I'm pretty confident you overloaded it. Just not the right motor for the job..... and one of the first thing that happens, is it overheats.... and on the mars motors, the brush holders melt, which you say it did.

It'l keep happening unless you A) Lighten up the total weight B) Change the ratio to limit top speed, but help the motor torque match what is required or C) Change the motor to something larger with more torque.


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## Duxuk (Jul 11, 2009)

This is all very worrying, but lets face it, a motorcycle with passenger weighs more than my single seater trike, which is why I supposed I'd be OK. I have the option to reduce the output volage to the motor. If I set the slider in the Alltrax software to 50%, the controller will only ever output 150amps. I presume this is 150amps at any voltage.

I will first try the performance with the slider set to about 125amps, since this is the one hour figure given by Mars. 

Would there still be any reason why the ampage in the motor would go above this figure?

The Alltrax manual is quite clear that the output current control does exactly what the name suggests, that is it controls the output current supplied to the motor. There are also other performance limiting controls in the software which I will study and set cautiously. BTW I didn't notice this problem starting to occur whilst driving quickly, but whilst moving the trike around standing beside it at a slow walking pace.

Thanks for your help.

Andrew.


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## Juiced (May 2, 2009)

Hey Andrew. 

What is the date code on the motor? It will be computer etched on the side. 

Juiced


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## Duxuk (Jul 11, 2009)

I spoke to John Fiorenza a Mars Electric and he has sent me a new brush holder. Both have been of the latest type.I have fitted it and limited the output current of the Alltrax 7234 to 120amps (the motor can take 125 for one hour). I have also sent for a ten toothsprocket to replace the twelve tooth, which wiil up the voltage at a given speed hence reducing the amps. It's very slow! Off the mark is pitifull but as the speed reaches about 15mph I get a bit of a power band and progress is acceptable. The new sprocket should help matters but I will just have see how it goes on the few hiils locally.

When I tried it up the road the motor didn't feel warm at all but I was suprised to find that the welding cable to the motor was warm. Is this normal or could I have something loose somewhere down the line?

I will probably turn the output amps uo a bit. Alltrax confirmed that the ampage control does what the name suggests. 

Andrew.


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## Duxuk (Jul 11, 2009)

The other day I looked at the connections on my reversing contactor and found the the negative was loose and the insulating cover was scorched. This might be the cause of my problems! The cables are no longer getting hot and performance has improved. I am going to change all the nylock nuts to plain nuts with spring washers since nylocks are obviously wrong, I now find!

Hindsight is such a wondeful thing, pity you don't get it before you get 'experience'!

Andrew.


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## sri (Sep 9, 2007)

Andrew,

I've had the same problem. There was sparking, the insulation burned off. The springs got damaged and the brushes withdrew and made occasional contact. The commutator was also slightly damaged but nothing that sanding won't fix.

This was on an EX250 Ninja with a Kelly PM72301 controller. When I opened the brush holder case, I discovered that a few contacts were loose (hadn't been adequately tightened). I believe this was the culprit.

Sri

PS. Image attached of inside of brush holder case.


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## Juiced (May 2, 2009)

It looks like you have one of the older brush packs. You need to contact Marrs Electric LLC to get a replacement.



EV Ed


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## Duxuk (Jul 11, 2009)

Hello,
just to update the thread which I started, I have had no problems since fitting the replacement brush holder. It was identical to the origional. I have used 180 and also 210 amps as the limits in the Alltrax controller. You set the limit and the motor is only allowed to draw the specified ampage regardless of voltage being supplied. I have checked the motor and wiring temperatures under load and they have been easily within the acceptale range so I think this should ensure a long life. Just need to get one new battery now since it's voltage sags under load. This is happening because I ran them down to flat about 20 times. It is to the credit of the batteries that only one has died. If I'd known then what I know now I would have kept my journies down to 10 miles or so but I was determined to drive 25 miles to work before recharging. This was a mistake since the voltage would sag to below the acceptable level for LA in the final few miles. AGMs might do better and I will probably go that way when I can afford it.

Andrew.


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