I'm using a brushless DC motor. The advertising claims it can deliver the torque we need. But, as we increase load, the motor get hot and slows to a stop. What's the fix? Should i:

1. Increase available current?
2. Increase voltage?
3. Get a new motor?

This table shows what we're seeing:

	LOAD	MEASURED TORQUE	SPEED	VOLTAGE	CURRENT DRAW
	(gms)	(Nm)	(RPM)	(V)	(Amp)
No Load	0	-	2100	4.54	0.48
Loaded	185	0.018	730	4.52	3.7
Motor stall	395	0.039	0	4.53	3.9

 

Does it come with driver? Any picture and dimension would help. These hobbyist BLDCs are 1S or 2S etc.

 

The advertising claims it can deliver the torque we need.

How much torque is that?
That BLDC motor doesn't look like it has much torque.
What are you attempting to accomplish?

 

Not much torque if you ask me. 1 ft lb. = 12 in lb.

 

FIRST, look atthe data sheet, not the advertising! And the motor performance graphs. OR possibly the units are wrong and the tourque is in gram centimeters?
Besides that, motors DO GET HOT! The name-plate often includes the temperature rise aabove ambiet. A 20 degree C. rise is hot.

 

The current at "load" and the current a "stall" are very similar. I do not think this motor will last at "load".

 

No datasheet, no torque spec given.

This is the motor-
https://www.amazon.in/dp/B0DNXPKPC9
"12V 100W 1300015000rpm 775 Motor High Speed Large Torque DC Motor"

Using with this converter:
https://www.amazon.in/dp/B09N2CFS93
"CC CV Buck Converter Module DC 6-40V to DC 1.2-36V Adjustable Step Down Voltage Regulator 20A 300W"

 

That is NOT a BLDC motor! obviously, it is a permanent magnet DC motor and it is too weak. The other link you provided is a buck convertor not a BLDC driver. If you really need torque from a small motor, you have to switch to BLDC which is way more expensive and even pricier driver needed to run it. What are you using this motor for??

 

The very first thing to do is verify that the motor supply voltage is correct, not dropping as the load increases. ALSO, as mentioned in post #8, it does not look at all like a brushless DC motor, but rather like a CHEAP brushed type PMDC motor. AND, after seeing the amazon listing, the picture verifies that it is not a BLDC motor. EASY to verify: it has only two terminals and no internal electronics.

 

Tech details of your motor indicate it is only 10 watt, so yes, it will run hot at your current draw.

 

Tech details of your motor indicate it is only 10 watt, so yes, it will run hot at your current draw.

Whie the small print describesthe motor as "ten watts", the big claim text calls it a 100 watt motor. At 12 volts that would mean it would require more than 8 amps, (8.333 amps).

SO it looks to me like an INTENTIONAL LIE in the main description, not a typographical error. Certainly like no checking for accuracy was involved.

 

Did you notice that the one reviewer gave it one star?

Also, it is listed as a 12V motor. Why are you running it at 4.5V? Do you expect to get the rated torque at that voltage?

 

No datasheet, no torque spec given.

This is the motor-
https://www.amazon.in/dp/B0DNXPKPC9
"12V 100W 1300015000rpm 775 Motor High Speed Large Torque DC Motor"

Using with this converter:
https://www.amazon.in/dp/B09N2CFS93
"CC CV Buck Converter Module DC 6-40V to DC 1.2-36V Adjustable Step Down Voltage Regulator 20A 300W"

Motor data shows that it requires 12V but in your table, supply voltage is around 4.5V. it should badly affect the torque and cause motor heating. And of course this is not a BLDC motor as already mentioned in comments. Title says 100W but specification says 10W only.

 

In Post #1 the TS shows a table listing torque in Newton Meters. Post #4 converts 0.018 into foot pounds of 0.013276. That comes to 0.159 inch pounds of torque. Little more than an old clock motor. That may be an oversimplification of the matter but in reality less than 1 inch pound is very very little.

I'm with others who are saying the numbers do not add up. Whether it's a 100W motor or 10W motor - what I'm seeing in your table does not suggest that little torque. And given that it's not a brushless motor - the ad is an outright lie. Yes, I looked at your link to the motor. In the "Specs" they say nothing about torque. So where did you get your table from?

 

That looks like a standard Johnson Electric DC motor. If it has an identification label you can get the specs on the their web site. As mentioned above, you will get very little torque running a 12VDC motor at 4.5 Volts.

 

True it is a DC brushed motor, I have a coupler of versions of this motor.
The appropriate controller is required, firstly for one.

 

where did you get your table from?

Our own tests.

appropriate controller is required

Why can't we run this with a CCCV converter? It turns on.

 

What type of load are you placing on the motor? what is it driving?

 

When I was a kid I imagined taking a 9 volt transistor battery and use it to power a full size automobile hundreds of miles on a single battery. Now that I've grown up and older, I know such a thing will never happen.

I share this because of the torque listed in your table. It works out to 2 1/2 inch ounces of torque. My grandchildren's toy pinwheels have more torque than that. I question your numbers or goals. They don't add up. And you haven't answered the questions "How much torque do you need?" "What type of load are you placing on the motor?" "What is it driving?"

you will get very little torque running a 12VDC motor at 4.5 Volts.

If at 12V you get 2 inch ounces of torque you'll barely have enough power to make the motor turn over running it on 4.5V. Let's assume 6 volts: at that voltage you'll have 1/4th the torque as you would get running at 12V. It's that inverse square law thing getting in the way. A motor rated for 10 inch pounds at 12 volts will only produce 2 1/2 inch pounds at 6 volts.

 

Here is the datasheet:
RS-775 High speed high torque 12V 24v micro DC motors | Foneacc Motor (foneacc-motion.com)