THE ORIGINAL MAGNETIC PARTICLE SPECIALISTS
Buy direct! Call or email today for a quote!
service@magne-power.com   888-776-2463

See Below for Magneclutch® and Magnebrake® Engineering Calculations on the following applications:

Magnetic Particle Clutch on a Powered Rewind
Magnetic Particle Clutch for Overload Protection
Magnetic Particle Clutch for Dynamometer Testing
Quick Selection - Heat Dissipation (Slip Watts) vs. Speed Chart (RPM)

Magnetic Particle Brake on a Non-Contact Unwind
Magnetic Particle Brake for Controlled Deceleration
Selection - Heat Dissipation (Slip Watts) vs. Speed Chart (RPM)

## Magnetic Particle Clutch on a Powered Rewind

Web Force (F)Web Speed (V)Core Diameter (d)Full Roll Diameter (D)Motor Speed
3.5 lbs. 1490 fpm 3.25 in. 16 in. 1750 rpm
##### 1. Calculate Torque (T)

T Start = 3.5 lbs. x 3.25in./24in. = 0.5 lb. ft.
T Finish = 3.5 lbs. x 16in/24in. = 2.3 lb. ft.

##### 2. Calculate Speed (RPM)

RPM = Velocity/π(diameter)
RPM Start = 1490 fpm / π x 3.25in/12in. = 1750 rpm
PRM Finish = 1490 fpm / π x 16in./12in. = 356 rpm

##### 3. Calculate Slipwatts (SW)

SW = T x (RPM in - RPM out) / 7.04
SW Start = 0
SW Finish = 2.3 lb. ft. x (1750 rpm - 356 rpm) / 7.04 = 455 Watts

##### 4. From Slipwatts vs RPM curves

The 10MC90B20 will dissipate 500 Watts at 1750 rpm.

## Magnetic Particle Clutch for Overload Protection

Torque Required at Conveyor (T Req)Speed of Conveyor Drive Roll (N Req)MotorGear Box Ratio
20 lb. ft. 175 rpm 1 hp @ 1750 rpm 10:1
##### 1. Calculate Torque at Clutch (T)

T = T Req / Ratio
T = 20 lb. ft. / 10 = 2.0 lb. ft.

##### 2. Calculate Speed at Clutch (RPM)

RPM = N Req x Ratio
RPM = 175 rpm x 10 = 1750 rpm

##### 3. Calculate Slipwatts (SW)

SW = T x RPM / 7.04
a. In normal operation, SW = 0
b. When a jam-up occurs: SW = 2.0 x 1750 / 7.04 = 497 Watts

##### 4. From Slipwatts vs RPM curves

The 10MC90B20 will dissipate 500 Watts at 1750 rpm

## Magnetic Particle Clutch for Dynamometer Testing

1/4 - 1 hp 1750 rpm
##### 1. Calculate Torque (T)

T = 5250 x hp/rpm
T Min = 5250 x 1/4 hp / 1750 rpm = .75 lb. ft.
T Max = 5250 x 1 hp / 1750 rpm = 3 lb. ft.

##### 2. Calculate Slipwatts (SW)

SW = T x RPM / 7.04
SW Min = .75 lb. ft. x 1750 rpm / 7.04 = 186 Watts
SW Max = 3 lb. ft. x 1750 rpm / 7.04 = 746 Watts

##### 3. From Slipwatts vs RPM curves

The 10MCA90B20 will dissipate 785 Watts at 1750 rpm.

## Magnetic Particle Brake on a Non-Contact Unwind

Web Force (F)Web Speed (V)Core Diameter (d)Full Roll Diameter (D)
12 lbs. 200 fpm 3 in. 30 in.
##### 1. Calculate Torque (T)

T Start = 12 lbs. x 30in./24in. = 15 lb. ft.
T Finish = 12 lbs. x 3in/24in. = 1.5 lb. ft.

##### 2. Calculate Speed (RPM)

RPM = Velocity/π(diameter)
RPM Start = 200 fpm / π x 30in./12in. = 25 rpm
RPM Finish = 200 fpm / π x 3in./12in. = 255 rpm

##### 3. Calculate Slipwatts (SW)

SW = T x RPM / 7.04
SW Start = 15 lb. ft. x 25 rpm / 7.04 = 53 Watts
SW Finish = 1.5 lb. ft. x 255 rpm / 7.04 = 54 Watts

##### 4. From Slipwatts vs RPM curves

The 25MB90S will dissipate 140 Watts at 255 rpm.

## Magnetic Particle Brake for Controlled Deceleration

1000 lb. ft.2 360 rpm 60 sec.
##### 1. Calculate Required Torque (T)

T = WK2 (rpm) / 308(t)
T = 1000 (360 rpm) / 308 x 60 = 19.5 lb. ft.

##### 2. Calculate Maximum Slipwatts (SW Max)

SW Max = T x RPM / 7.04
SW Max = 19.5 lb. ft. x 360 rpm / 7.04
SW Max = 997 Watts

##### 3. Calculate Average Slipwatts (SW Avg)

SW Avg = √[(t on / t on + t off) x 1/3 x SW Max2)]
SW Avg = √ [(1 min. / 2 min.) x 1/3 x 9972)]

SW Avg = 407 Watts
##### 4. From Slipwatts vs RPM curves

The 50MB90B20 will dissipate 450 Watts at 360 rpm.