Voltage Drop and Voltage Drop Testing

Voltage drop is a decrease in voltage along a conductor through which current is flowing. All conductors offer some resistance to the flow of electricity, and in plant vehicle electrics, it is important that we minimise the drop in voltage that this resistance causes.

For example, when supplying the starter motor with current, it is important to keep the heavy cable runs between the starter and the battery as short as possible. This helps minimise voltage drop. If voltage drop in a starting circuit were excessive, it would lead to starting problems, and the motor would tend to overheat or even burn out.

Voltage Drop Testing

If you suspect that a component or a particular circuit is causing a voltage drop, you can put a voltmeter in parallel with that component or circuit, operate the circuit and observe the readings on the voltmeter. This strategy is used when testing starting circuits and charging circuits.

REMEMBER: Voltage drop testing is only useful when the circuit is fully loaded and carrying its normal working current.

» Course Glossary


Please note, if you want to contact the main Training Centre in Baldoyle, you need to ring 01-8167400.

If you want to contact the CP Fitters' Section, you can Contact Us by email, admin@cpfitters.info, or by telephone: 00 353 1 8167543 This number gets you through to the CP Fitters' Section, Baldoyle Satellite Unit.

Our Address is : Construction Plant Fitters' Section, Unit 116, Grange Way, Baldoyle Industrial Estate, Baldoyle, Dublin D13 CA48.
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