Burden Sales Surplus Motor Frame Dimensions Chart printable pdf download

Burden Sales Surplus Motor Frame Dimensions Chart

BURDEN SALES SURPLUS CENTER

NEMA Frame/Shaft Sizes

Frame numbers are not intended to indicate electrical characteristics such as

horsepower. However, as a frame number becomes higher SC) in general does the

physical size of the motor and the horsepower. There are many motors of the same

horsepower built in different frames. NEMA (National Electrical Manufacturers

Association) frame size refers to mounting only and has no direct bearing on the motor

body diameter.

In any standard frame number designation there are either two or three numbers.

Typical examples of frame numbers 48, 56, 145, and 215. The frame number relates to

the “D” dimension (distance from center of shaft to center bottom of mount). For

example, in the two-digit 56 frame, the “D” dimension is 3½”, 56 divided by 16 = 3½”.

For the “D” dimension of a three-digit frame number, consider only the first two digits

and use the divisor 4. In frame number 145, for example, the first two digits divided by

the constant 4 is equal to the “D” dimension, 14 divided by 4 = 3½”. Similarly, the “D”

dimension of a 213 frame motor is 5¼”, 21 divided by 4 = 5¼”.

By NEMA definition, two—digit frame numbers are fractional frames even though 1 HP

or larger motors may be built in them. Three-digit frame numbers are by definition

integral frames. The third numeral indicates the distance between the mounting holes

parallel to the base. It has no significance in a footless motor.

A summary of NEMA standard dimensions is on the next page.

Burden Sales Surplus Motor Frame Dimensions Chart