48V nema23/34 servo motors

[ee_t]

I've been on a quest for some low cost nema23/34 servo's, around 4-600W range.

Torkmotion/Techsoftmotion:

Not sure what the relationship is between the two companies. Techsoftmotion lists a lot of torkmotions products. Torkmotion did not reply to my email. Techsoftmotion replied with some sample pricing (450W nema23 ~$150), but later retracted saying they "paused international business, because they were too busy and cant deliver on time".
Their motors look good though, nema23 goes up to 613W. Nema34 available as well, but rated at 90V. One odd thing is that both front/rear shafts are sized at 3/8" (could spec otherwise if you buy enough).


Kelinginc:

Their 4 pole nema23's are cheap but not very useful IMO, best is ~220W input with an output of 0.4Nm.

Moving to the 8 pole nema34's, specs are much better. On par or better than the others I've looked at except in one area: weight. They weigh a ton, the largest is 4kg (KL34BLS-125), with a rotor inertia of 2.4kg-cm². A comparable nema34 from torkmotion weighs less than half, and 1/4 the rotor inertia. I guess they cheap out on the magnets?


Longwaymotor:

They have a wide selection of motors. 185W out nema23: 57BL3A90-C has higher weight than the keling nema23's but better torque rating. Although probably too low to be useful to me.
I was given a sample price of $50 (lower specced keling is $52), and 10,000 pc quantity price is down around $25 :P.


Tempted by the Keling 98 or 125, but the 4kg weight really turns me off.
If anyone has some alternatives, please post. I will continue to browse ebay for the moment.

[Mariss Freimanis]

You will never get 613W from a NEMA23 motor unless it's used to drive a torpedo where 30 seconds of motor lifetime is more than plenty.:-) Here's why:

At best, a servomotor is 75% efficient when it's delivering it's rated power. At 613 Watts out, power in is 613W / 0.75 or 817 Watts. The difference (817W in - 613W out) is 204 Watts. Those 204 Watts go up as heat in the motor and a NEMA23 package size dissipating 204 Watts would make for a very nice barbecue grill. The motor will be smoking hot, great for grilling White Castle size hamburger patties.:-)

250W from a NEMA23 size motor is an excellent power output. Don't believe everything you read or you will be a victim of ridiculous specifications.

Mariss

[Tormachmaster]

Hey just go to Keling cnc servo and stepper parts they are great and have everything you want and cheaper I have bought from them several times they are great.

[ee_t]

Originally Posted by Mariss Freimanis You will never get 613W from a NEMA23 motor unless it's used to drive a torpedo where 30 seconds of motor lifetime is more than plenty.:-) Here's why: At best, a servomotor is 75% efficient when it's delivering it's rated power. At 613 Watts out, power in is 613W / 0.75 or 817 Watts. The difference (817W in - 613W out) is 204 Watts. Those 204 Watts go up as heat in the motor and a NEMA23 package size dissipating 204 Watts would make for a very nice barbecue grill. The motor will be smoking hot, great for grilling White Castle size hamburger patties.:-) 250W from a NEMA23 size motor is an excellent power output. Don't believe everything you read or you will be a victim of ridiculous specifications. Mariss

Thanks for the reality check .
Appreciate your posts and really looking forward to the new drives.

Originally Posted by Tormachmaster Hey just go to Keling cnc servo and stepper parts they are great and have everything you want and cheaper I have bought from them several times they are great.

Just surprised that google showed nothing for the nema34 models. I had skipped over the 23's as I was swayed by unrealistic specs. Although there is still very little discussion of them (I suspect that will change with a new BLDC gecko).


btw if anyone else is reading, some excellent discussion in here: affordable brushless motors.
As well as the step motor servo thread, where Mariss used a KL23BLS.