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Click Here to Learn More!The following are some of the key comparison factors that are used in evaluating a Brake or a Clutch Product. These factors are used to compare a Pneumatic Brake with an Electric Brake.
Electric Brake vs. Pneumatic Brake in Tension Control Applications:
Response Time
Response time is the increment of time in seconds from the time the power is turned on or off at the control valve, or power supply, to the time the clutch or brake responds with (full load) torque, or disengages and the torque begins to decay. The time to 100% clutch torque for the air clutch was 40% faster than for the electric clutch. The time to zero torque (brake on) for the air clutch was 42% faster than for the electric.
Torque Output
Tests focused on the torque output of NEMA 56 C-flanged air and electric clutch-brakes. The electric clutch transmitted only 54% of its rated torque. In comparison, the Pneumatic clutch transmitted up to 145% more torque under the same conditions, because it operated at a lower temperature. The higher operating temperature of the electric clutch affected torque fade, as well.
Facing Life Comparison
The estimated facing life of air and electric units were determined in a calculation using the 1) volume of useable facing material, 2) friction materials wear rate, 3) work energy capacity, and 4) energy-per-cycle for a specific application. The results indicated that the Pneumatic clutch-brake had considerably more available facing volume, which translates into more horsepower-hours of work. While the pads on the Pneumatic unit were worn away partially, they still had sufficient material left to create the required friction against the facings to start or stop the load on the output shaft. The pads on the electric unit, on the other hand, were worn so far down that there was metal-to-metal contact.
Thermal Horsepower
The test also revealed that the air clutch-brake consistently operated at lower temperatures compared to the electric unit. The Pneumatic unit tested had a rated thermal horsepower of 0.14. A comparable electric unit has a rated thermal horsepower of 0.10.
Repair Costs
A test to determine the number of cycles to failure was conducted, and the Pneumatic clutch-brake was the overwhelming winner, more than doubling the number of cycles achieved by the electric unit. Additionally, replacement part costs published by the manufacturers showed that the air unit is less expensive to repair.
Energy Consumption
Using Friction Facing Life comparison information gathered in a conveyor system application, along with power consumption data published in the electric clutch-brake manufacturer’s catalog, it was discovered that the electric unit coil consumed 2.5 times more energy than the compressor that provided air to the Pneumatic unit.
Unit Cost Savings
There are typically cost savings in using the Pneumatic unit instead of an Electric Clutch-Brake, both in the brake itself, and also in the electronic control conversion.
