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Series/parallel, Shorts, Opens – Cub Cadet Z-Force S Series User Manual

Page 122: Increased resistance

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Z-Force-S

116

Series/parallel

Series/parallel circuits have some sections wired in

series and some in parallel. See Figure 7.40.

What can go wrong?

There are three types of failures that can occur in an electrical circuit:

1.

Shorts

2.

Opens

3.

Increased resistance

Shorts

A short is when electricity takes a path that it was not designed to take by-passing a component in the circuit.

A common example of a short is a wire with insulation that chafed through, exposing the copper conductor. The

bare copper will short the circuit when it touches a ground source.

Opens

An open is when current can not complete its path back to the power source. A common example of this is a

burned-out lamp (light bulb) in a series circuit.

Increased resistance

Increased resistance is, as the name implies, an increase in resistance.

This can be caused by loose or corroded connections, or connections that are insulated by grease, paint, or coat-

ings. Fasteners finished in oil/phosphate or black oxide are bad conductors. Use bright fasteners (zinc coated).

Resistance can be a problem on the ground side as well as the hot side of a system. Remember that electricity

must complete a loop (circuit) back to the battery post. Any resistance in that loop will interfere with the flow.

Arguably the most common electrical failure, and the hardest to find, increased resistance can have more subtle

symptoms than outright open circuits. Many times affected circuits will still partially function. It is not an open because
there is some current that can get through, but the increase in resistance is enough to affect the circuit.

Figure 7.40

Battery

Lamp Switch

Lamp

Lamp

Lamp