What do I do? 12VDC 100w motor

[stk2008]

Hi all I am trying to run a 12VDC 100w motor on me sons gokart but I have a problem.

I have the motor a 12V 9amp/hr battery and a switch as throttle but it has no torque.
Even if I lift the wheels off the floor it takes a few seconds to spin up and then it goes like the clappers.

The motor came from a scooter but I have been reading it all so came with a controller whice I dont have .

Does the controller increase the amps to in turn increase torque.

If I do need a controller can I make one simple enough or are they cheap?.

Thanks in advance

 

[ronsimpson]

has no torque.
Even if I lift the wheels off the floor it takes a few seconds to spin up and then it goes like the clappers.

I think you are saying it goes very fast with little torque.
The motor need to be geared down. So the wheels go slower and the motor goes faster.

 

[stk2008]

Hi thanks for replying.

I am all most certian now that the scooter it came from had some kind of controller.

If I press the throttle (simple on of switch) when the wheels are on the floor the go kart does nothing its all most as if the battery is flat.

If I lift the wheels in the air the wheels will go faster and faster.

I have done some reading and every site makes ref to a controller for DIY go karts using motors like mine.

12VDC 100w motor.

Some people refer the the controller being able to output 40amps and more this would explain there torque gains.

My mate said the scooter my motor came from did have some kind of box but he threw it away

 

[stk2008]

Some thing like this I do believe

**broken link removed**

 

[tcmtech]

A 100 watt motor is pretty weak for a gocart. My brother has RC toys that run far higher wattages than that.

I set up a electric scooter for my niece that is running a 600 watt motor and thats about right for her 75 pound body and the 25 pound scooter. For me and her dad however, at 250 pounds, it doesn't get very far very fast when we ride it.

Any idea what yor battery voltage pulls down to when you load it up?

 

[stk2008]

Hi there thanks for replying

The motor came from a scooter and my mate rode it before ripping it a part he said it went really well with him on it and he is a big man but now it has no power at all.

I dont know the voltage when under load I can check I assume I hook up me multimeter to battery run engine and see what the volts drop to??????????.

Thanks

 

[panic mode]

sounds like the magic is gone (in a cloud of smoke)

 

[Boncuk]

Hi panic mode, the magic isn't gone yet.

Please read carefully:

12V 9amp/hr battery.

It's not easy to interpret the post correctly, but that's my idea about the low performance.

The battery will be depleted faster than the motor is able to attain full rpm at full torque.

(A 9Ah battery is just too weak!)

Boncuk

 

[4pyros]

Yes you need to try it with a bigger battery.
Also you have not told us how you geared it.
The gearing is vary important.
Sounds like it is not a geared motor.

 

[stk2008]

Hi all thanks for helping.

I just spoke to my mate and he said he had it working using a car battery.

I am still convinced it has one of them controller boxes before on the scooter.

The motor is not geared just the gears fron the original gokart.

I have noticed all so that when I lift the kart off the floor and run the wheels all the wires get hot and the connections is this because the motor is pulling to much amps then the wires can handle or because the battery cant handle the rqiured amps needed?

EDIT
Though if I wire the motor directly to the battey the motor wires still get hot so must be the battery surely?

 

[tcmtech]

If the wiring is large enough (12 ga should be more than enough) and still gets hot without any load on the motor the motor is most likely cooked and has partially shorted windings in it.

Hope you didn't pay too much for it!

 

[stk2008]

ah ok well the wires that are on the motor as std get hot so I would assume some thing is wrong.

 

[4pyros]

It may be that without the controller you are giving it to much power but more likely it is a bad motor if you are shore it is a 12 volt motor and you are running it off 12 volts.
Is there any friction in the drive? If you take the motor out or disconnect the drive and run it with nothing connected to it do the wires still get hot?

 

[stk2008]

hi there yep its deffo a 12v motor says so on the tin and its a 100w motor to its all so says so on a sticker.

i will take the motor out tomorrow and test on the bench.

Shame this as me son was looking forward to driving it.

Its odd becuase there really is no torque in the motor maybe there is a coil broke in it some where?

 

[tcmtech]

Unfortunately if its drawing high amps at no load it is not a broken wire issues but rather the insulation has been burned right off them and they are shorted out in multiple places. A 100 watt 12 volt motor should only draw 1 - 2 amps no load and around 9 at full rated load.

Odds are if you take it apart you find the commutator is burned blue and the enamel insulation on the windings is burnt black and falling apart.

 

[stk2008]

meaning its no good or could be fixed......for free I mean could I fix it or once that happens it needs to be done professionaly ?.

p.S

if the windings etc are burnt out how could this have happend?

 

[4pyros]

if the windings etc are burnt out how could this have happend?

Big guy on scooter.

 

[stk2008]

LOL fair enough.

 

[panic mode]

as i told you, magic is gone. electrical devices operate on smoke so don't let the smoke out... ;p

 

[stk2008]

ok update

Ran the motor out of the kart and its runs with out any wires getting hot etc.

It just lacks torque in the gokart.