DC 775 motor relation with voltage and amps?

Hi guys, I have a small project I'm running using DC 775 motor as a grinder, cutter and drill. My DC 775 motor is rated as 12-24v 5A (Min). Silly me, I tried to power this motor with 24v 2A adaptor which failed badly, the motor turns on in pulses due to insufficient amps. I'm looking to ensure that the motor is powerful enough to within grinding, drilling and cutting through steel (preheat treated, soft). I've been wondering, which would determine a more powerful motor (speed+torque), voltage or amp? Will a 12v 8A power it better than a 24v 5A?

I have found other alternatives, I could use a SMPS or an adaptor. However, Idk which should I use to obtain optimal power, speed, etc..

SMPS options
24v 10A
24v 15A
24v 17A
Is it safe to exceed the minimum amp of the motor? Since the motor is rated with a minimum 5A? Will exceeding this affect the motor in any way in the long run?

Or there's this adaptor which is rated at 24v 5A. Do you guys reckon this 24v 5A adaptor would be sufficient enough to power the motor to my goals as above ? There is another adaptor rated at 12v 8A instead, will this power the motor far better?

Link to the adaptor : https://shopee.com.my/product/48932981/1037026964?smtt=0.55944417-1607772975.9

Personally I'd prefer an adaptor over a SMPS power supply board (as I have 0 knowledge in electrical stuff and wouldn't wanna get fried while assembling it).

Thanks.

An example of the 775 motor: 775 motor dc 12v-36v 3500-9000rpm motor large torque high power motor Sale - Banggood.com sold out-arrival notice-arrival notice.

A SMPS is a switched power supply (I did not know what SMPS was).

Do you want to keep the 775 motor ?
Then you have to know its "stall current". That is the maximum current in the most worst situation that the motor might draw. If the average current is 4A, then the stall current could be 40A.

Once you know the stall current, then you need a driver (the module that drives the motor) that can supply that. It is okay if it can drive more current. Do you use a driver board ? or is this without Arduino board ?
Then you need a power supply that also can supply that. It is okay if the power supply has more current.

When the motor is 12V-24V, then it is probably a 24V motor that also runs at 12V. So you need a 24V power supply.
Sometimes the motor is made for, for example, 16V and will get too hot at 24V. A motor of a good brand can run at 24V continuously.

I can find 775 DC motors that are 12V, they are rated as 6-20V. So you really have to know the specifications of your motor.

There are many different 775 motors with different windings and so current ratings. 775 is just the physical size. A specification of the one you have would help. Also more details of what you’re doing with it. E.g. size of drills, cutters and how long you expect to run it for.

Unfortunately 5A “minimum” is meaningless. As soon as you start loading the motor by making it drill or cut something the current will shoot up. A 775 is typically 300W rated so at 24V full power would be at around 12-15A. Without knowing the details of exactly what motor you have I’d probably look for at least 24V 15A.

Steve

Koepel:
An example of the 775 motor: 775 motor dc 12v-36v 3500-9000rpm motor large torque high power motor Sale - Banggood.com sold out-arrival notice-arrival notice.

A SMPS is a switched power supply (I did not know what SMPS was).

Do you want to keep the 775 motor ?
Then you have to know its "stall current". That is the maximum current in the most worst situation that the motor might draw. If the average current is 4A, then the stall current could be 40A.

Once you know the stall current, then you need a driver (the module that drives the motor) that can supply that. It is okay if it can drive more current. Do you use a driver board ? or is this without Arduino board ?
Then you need a power supply that also can supply that. It is okay if the power supply has more current.

When the motor is 12V-24V, then it is probably a 24V motor that also runs at 12V. So you need a 24V power supply.
Sometimes the motor is made for, for example, 16V and will get too hot at 24V. A motor of a good brand can run at 24V continuously.

I can find 775 DC motors that are 12V, they are rated as 6-20V. So you really have to know the specifications of your motor.

Thanks for the reply! I'm not too sure about the specs on my motor or what a driver board is, still relatively new in electrical stuff. As for the motor specs, the seller only provided these info's:

Rated DC voltage: 12-24v
DC Power supply: 5A minimum
No load speed 12v @6,000rpm
No load speed 24v @12,000 rpm
Wattage: 80w
Imported carbon brush

Link:
https://shopee.com.my/product/53171392/2159586055?smtt=0.55944417-1607782042.9

I hope I've used the right name for the SMPS, here's what I was talking about

Link:
https://shopee.com.my/product/22959997/4709590826?smtt=0.55944417-1607782155.9

Thinking of getting the 24v 15A, do you think it'd differ greatly than a 24v 5A adaptor? As the amps is high on the former than the latter.
Thanks!

slipstick:
There are many different 775 motors with different windings and so current ratings. 775 is just the physical size. A specification of the one you have would help. Also more details of what you're doing with it. E.g. size of drills, cutters and how long you expect to run it for.

Unfortunately 5A "minimum" is meaningless. As soon as you start loading the motor by making it drill or cut something the current will shoot up. A 775 is typically 300W rated so at 24V full power would be at around 12-15A. Without knowing the details of exactly what motor you have I'd probably look for at least 24V 15A.

Steve

Hi, thanks for the guidance. There's not much details on the motor specs, the seller only provided these info:
Rated DC voltage: 12-24v
DC Power supply: 5A minimum
No load speed 12v @6,000rpm
No load speed 24v @12,000 rpm
Wattage: 80w
Imported carbon brush

Link: https://shopee.com.my/product/53171392/2159586055?smtt=0.55944417-1607782042.9

Here's what I'm making with the motor

  1. bench sander
  • intending to grind 0.8mm thick steel (pre heat treat, soft) on a 60 grit paper
  • I'm estimating it'd run for at least 10 mins or less with breaks in between?
  • will also be grinding other materials like wood, resin, etc...of various thickness, but not exceeding 2cm for these.
  1. a bench saw/grinder
  • intending to cut 0.8mm steel with a disc (0.3-0.5mm thick disc)
  • estimated time probably less than 10 mins?
  • will be cutting other materials like wood and resin material too, usually less than 50mm thick
  1. drill press
  • intending to drill through 0.8mm thick steel, wood, etc..
  • not too sure how much time this will run for, since the rpm is high on this, I was thinking of taking "breaks" in between drilling still as to prevent overheating and blunting of the drillbit.

Those are my plans with the motor.

I guess the 24v 15A smps/power supply unit would be a better option than the 24v 5A adaptor? How would they differ, if u may ask? I'm assuming the amps?

24v 15A Power supply unit
Link: https://shopee.com.my/product/22959997/4709590826?smtt=0.55944417-1607782155.9

24v 5A adaptor
Link: https://shopee.com.my/product/48932981/1037026964?smtt=0.55944417-1607782870.9

Thanks

You can quickly eliminate the power supply problem by using one or two 12 volt automobile batteries to supply power to test your equipment.

Paul

As the motor is only specified as 80W (very low for a 775) then since 24V x 5A is 120W it should be enough if everything works as specified.

As for whether 12V or 24V would be better that depends on how fast you need the motor to turn. As the spec says 24V goes twice as fast as 12V but 12V. I don't know what speed your tools will work best at. And remember that 12V needs twice the current of 24V so it would e 24V 5A or 12V 10A.

Steve

slipstick:
As the motor is only specified as 80W (very low for a 775) then since 24V x 5A is 120W it should be enough if everything works as specified.

As for whether 12V or 24V would be better that depends on how fast you need the motor to turn. As the spec says 24V goes twice as fast as 12V but 12V. I don't know what speed your tools will work best at. And remember that 12V needs twice the current of 24V so it would e 24V 5A or 12V 10A.

Steve

Thank you Steve. This is what I needed to know! I was contemplating between the 24v 15A and a 24v 5A power supply, not too sure whether it'd make a difference on the motor since they're both 24v? Was a bit worried that 15A would blow the motor lol
Thanks!

80 watts is not much for a bench grinder or a drill press. Most tools like that would use 1/4 to 1/3 HP (200 - 250 watts).