Using relays

[Howard LewisParticipant @howardlewis46836]

The safest way would be to use relays. A low current controls the supply to the coil of the relay, and the contacts control the high current supply to the motor.

What follows is on the assumption that the systen is either 12 or 24 volt DC.

If 12 volt then use a relay(s) from a car. If 24 volt then use a relay(s) fron a commercial vehicle such as a bus, coach, or lorry.

The relay coil has a light duty feed from the negative.

The other side of the coil has a light duty feed through the ON/OFF switch from the positive.

The heavy duty Negative feed goes direct to the motor.

A heavy duty feed from the Positive goes to one of the relay contacts. The other relay contact takes a heavy duty feed to the other side of the motor.

Since the motor is DC, if it rotates in the wrong direction, reverse the connections at the motor.

If there is a need to have the motor reversaible, things become a little more complicated, in that a two pole changeover relay is needed in the heavy duty feeds to the motor.

For this, if the coil is not energised, the motor goes Forward.  If the coil is energised, the motor goes in Reverse.

Alternatively, the single pole circuit could be duplicated, but with the motor feeds reversed on one of them.

This makes things more complicated

In this configuration the two ON/OFF switches, have a light duty feed from either sides of the Forward / Reverse switch.

Having selected Forward, the ON/OFF switch for the Forward circuit is used.

For Reverse, select Reverse and the use the ON/OFF switch for the Reverse circuit.

HTH

Howard

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