Pulse Operation of DC Solenoids
Technical Bulletin 104
Benefits of pulse operation:
No inductive transients with pulse operation
Operation of d-c solenoids with a-c power
Pulsing accommodates the use of higher voltage
No need for a well regulated power supply
Increasing solenoid force and decreasing response time
Lower solenoid temperature for continuously energized applications
Pulse operation overcomes the fundamental problems of d-c solenoids without incurring the usual disadvantages.
Disadvantages of d-c solenoids (not pulsed):
d-c coil windings cause an inductive transient (an arc) at the contacts of the switches or relays in the circuit.
d-c solenoids require a regulated dc power supply.
d-c solenoids are sensitive to temperature. The minimum operating voltage increases with temperature.
They cannot tolerate large variations in supply voltage. Over-voltage increases coil temperature, in turn increasing the minimum operating voltage.
With pulse operation, the solenoid is energized momentarily with five to six times its rated voltage, then held in with less than half of its rated voltage. Application time is reduced drastically and the reduced holding voltage produces less arcing when the circuit is opened. Additionally, a well regulated d-c power supply is not required.
For pulse operation of solenoids from a d-c source, a simple R-C circuit is required.
Pulse operation circuit for d-c operation.