Magnetic Technologies Products

Selection Criteria

How To Select
Selection Criteria and Calculations
For every application determine the TORQUE, MAXIMUM RPM, and for brakes, the BENDING MOMENT.
Then you can choose the correct shaft or coupling, and various accessories.


Three Steps to Selection	Example Selection Criteria
		Metric	English
	Line Tension (T)	8 N	1.8 lb
	Spool Weight (W)	134 N	30 lb
	Full Spool Radius (r)	0.15 m	5.9 in
	Spool Core Diameter (d)	0.125 m	0.41 ft
	Spool Centerline Distance (L)	0.11 m	4.5 in
	Line Speed	90 m/min	295 ft/min

Step 1 - Torque
The line tension multiplied by the radius of a full spool.

Example:
Full Spool Radius (r) x Line Tension (T) = Torque

.15 m x 8 N = 1.2 Nm
5.9 in x 1.8 lb = 10.6 in lb

Selection: In this example Model 523 or larger will work.

Step 2 - Bending Moment
The total weight multiplied by the Spool Centerline Distance (L).

Example:
Spool Weight (W) x Spool Centerline Distance (L) = Bending Moment

134 N x .11 m = 14.7 Nm
30 lb x 4.5 in = 135 in lb

Selection: In this example Model 610 or larger will work.

Step 3 - Calculate MAX RPM
When a magnetic brake shaft is turning, mechanical energy is converted into thermal energy (watts). The amount of thermal energy (watts) is a function of the RPM and the TORQUE SETTING.

Example Calculation:	Max RPM	=	Line Speed	=	90m/min	=	295 ft/min	=	229 RPM
			3.14 x Core Dia.(d)		3.14 x .125m		3.14 x .41 ft.

With the torque calculated in Step 1 and the maximum RPM calculated in
Step 3, refer to the operating curves to determine if your application is within the safe operating range of the brake.

Selection: In this example, Model 523 or larger will work, however...

CONSIDERING TORQUE, BENDING MOMENT, AND MAX RPM, THE BEST CHOICE IS MODEL 610.

At the bottom of each product page you will find an operating curve for calculating the safe RPM vs. Torque