Understanding motor frame sizes

[brandon_costa]

Hello,

For the motor frame size that I have chosen as per IEC/IS standard, there's a mention of small,medium,large with frame number. My question is what is the difference between small, medium & large? And if we choose one size higher than standard frame what will be the advantage? Is there any relationship with frame size & motor efficiency? I appreciate your kind advice.

[magicniner]

I chose small frame for the 1hp spindle motor on my little benchtop CNC mill, it's more compact than standard for the power and cost more but performance is near identical. It allowed me to go for more power than would fit on the machine in a standard frame size.

[brandon_costa]

Here's a good article on the subject.

https://precisionautomation.net/2019/04/18/the-mystery-of-motor-frame-size/ (https://precisionautomation.net/2019/04/18/the-mystery-of-motor-frame-size/)