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Topic: 12 volt DC brushed motor running fine on battery but not on wall adaptor. (Read 329 times) previous topic - next topic

shantanuonline

Hello Makers,

I have few projects in mind with DC motors but I just cant even get the motor running at first and need some help.

I have RS 550 12 Volt motor (see attached image for reference) which runs perfectly when connected with 12 volt battery as the speed gradually increased in few seconds but when I connect it with my laptop adaptor it just turn like few millisecond and then stop completely.

then I have to power off and on again and it again just do the same thing. I have read the forum and it looks like there is something with stall current or ampere it needs to be run but I am not sure what exactly I need to do to for my motor to run with my adaptor which is of 19..5 v 3.34 amp 65 watt AC adaptor.

I have checked the same motor with my friends adaptor which is of 16 volt 5 ampere but issue is same.

Any help will be appreciated.

slipstick

That's a large motor. A 12V battery will supply as much current as needed. When you try to run the motor on a higher voltage it will also take more current, and that is probably more than the supply can provide. Oh and when the motor actually has any load, i.e. if it is driving anything, it will need even more current.

The only real way to find out what is going on is to measure the current going into the motor on 12V.

Steve

shantanuonline

@steve, ok I connected amp millimeter in series while the motor is connected with said wall adaptor and its reads 19.75, as I said the motor don't run so not sure if you mean I should connect it with battery? because currently I don't have battery with me to test it.

Update: sorry about that wrong reading, looks like I did something wrong

shantanuonline

sorry about wrong figures, my connection was wrong. Actually why because the motor is not turning my amp meter doesn't show any reading, fir the first few milliseconds the motor turns that time I can see my meter reading like .10 or .2 and then it stops.

my millimeter can read 10 amp at max. Do I have any other option to check while I don't have the battery ? or I have check in some other way.

slipstick

Do you have any load on the motor or is it just spinning freely? I wouldn't expect more than about 3A if it's just running not connected to anything.

19.75 sounds like you were measuring the voltage. That's useful and it might be worth seeing if you can see that voltage dropping sharply when you first connect the motor. That's a good indication that it's drawing too much current...but don't try it too often or you could damage your adaptor.

Steve

Paul_KD7HB

sorry about wrong figures, my connection was wrong. Actually why because the motor is not turning my amp meter doesn't show any reading, fir the first few milliseconds the motor turns that time I can see my meter reading like .10 or .2 and then it stops.

my millimeter can read 10 amp at max. Do I have any other option to check while I don't have the battery ? or I have check in some other way.
IF you have exceeded the 10 amp maximum, you probably popped the fuse inside the meter.

Paul

shantanuonline

@steve, looks like i need to have a 12 volt battry to test the amp properly which currently i dont have, i have couple of 18650 with which i will create a temp powerbank and try to power the motor by conneting all 4 18650 in series and will take those readings you have mentioned.

@paul, luckly my multimeter survived, i need to be more cautious from next time☺️.

neiklot

IF you have exceeded the 10 amp maximum, you probably popped the fuse inside the meter.
I popped the 10A fuse in my Fluke a while back; genuine SIBA replacement costs more than most cheap meters.


shantanuonline

@steve, meanwhile I connected the motor with my 5 volt wall charger and motor start running at relative speed without any issue, do you think this can help investigating things more?

MarkT

Many budget multimeters don't have a fuse on the high current setting, just a big copper shunt bar which should
survive a reasonable degree of overload.  If you melt that, the meter is probably on fire anyway!

Never leave a multimeter connected to the 10A socket - its all too easy to forget and use it as a short-circuit
when you next go to measure a voltage, damaging something!
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

detown

That motor has a stall current of 72A. Google HRS550S motor.

shantanuonline

@detown, I have a 12 volt 2 ampere wall adaptor, is there a way I can draw that much of stall current to start the motor? for now when I connect the motor start spinning and then stop and the loop just go on.

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