DC Chopper

This kit consists of a power circuit and a firing circuit

POWER CIRCUIT:

This unit consists of 2 SCRs, 2 Diodes, Commutation capacitor and a tightly coupled center tapped inductance. All devices are mounted on a heat sink and protected by snubber circuit and fuse. All the connections are brought out to front panel. Different chopper configurations including Jones Chopper can be formed by different inter connections. A separate bridge rectifier is provided for field supply of DC motor. A DC circuit breaker is provided in series with the input terminals for 220V input model. This unit can be used for R, R-L and motor load. AC input versions are also available. The entire setup is enclosed in powder coated MS box.

FIRING CIRCUIT:

The firing unit can either be analog based or microcontroller based.

Analog firing circuit:

This unit generates firing pulses to trigger two SCRs connected in different configurations. This unit is based on timer oscillator, ramp generator, op amp comparator and pulse transformer amplifier isolation method. There are two potentiometers to vary duty cycle and frequency. Test points are provided to study logic circuit.

Microcontroller firing circuit.

This unit generates firing pulses to the SCRs based on a programmed microcontroller. Display is provided to indicate firing angle and duty cycle. Both duty cycle and frequency can be varied by using provided switches.

Both firing circuits work on 230V AC mains and are enclosed in powder coated MS box.