Ch 9 – Cranking Starting Systems: Heavy Duty Truck Systems

Cranking Charging Systems in Heavy Duty Trucks 5th Edition by Sean Bennett

Answers to Review Question for Diesel Mechanic Trade Schools in America.

Q: What does a 39MT starter motor use to produce high output torque combined with light weight?

Planetary Gearset

Q: If you are bypassing a starter relay switch using a jumper wire, what component is being tested?

Starter Relay Switch

Q: What percentage of starter motors returned under warranty are tested to perform to specification by the OEM?

80%

Q: Technician A says that the starter motor used to crank diesel engines can draw up to 400 amps of current. Technician B says that high resistance on the insulated side of a starter motor circuit would cause higher than specified starter motor current draw. Who is correct?

Both A and B

Technician A says that you should check the starter relay by bypassing it in the circuit with a jumper wire. Technician B says that you should check the relay using a voltmeter connected across the relay winding from the ignition or push button connection to vehicle ground. Who is right?

Both A and B

A starter thermal limit switch will prevent the starter from operating when the starter overheats?

Usually will reset after five minutes

Q: Which of the following components connects the cranking control circuit with the starter motor high current circuit?

Starter Relay