Cut-Out Relays for 32E Generators

Reverse current relays

Reverse current relays - or better - reverse current cut-off relays, are an important part of the early electrics, i.e. on J models and B and BA models. The side-valve (D, R, V, U, K models) and first OHV models (Knucklehead, Panhead until 1957, Sportster 1957) also had such relays. In short: all models with DC generators with three brushes.

What does the reverse current relay do?

It disconnects the generator from the rest of the circuit as long as the engine is not running and it is not charging. This prevents the generator winding (called the armature) from discharging the battery. The armature winding has a small electrical resistance and without a reverse current relay it would allow high currents to pass. And especially when starting the engine, you absolutely don´t want the current to choose the wrong path.

Why Solid State? What is Solid State?

Solid state means that semiconductor components are used. If you replace an originally mechanical relay with semiconductor components on a circuit board, you eliminate mechanics that require maintenance and are susceptible to vibrations, and you gain reliability and operational safety. Correctly selected, a silicon diode lasts many years longer than coil-controlled contacts. And there is no need to readjust the contacts.