Extech Instruments 380363 User Manual page 8

Applications
Measuring Power Tools and Small Appliances
This section applies to any device under test that uses a
line cord. For double insulated power tools, the meter's
leads should be connected to the device's housing (chuck,
blade, etc.) and to the lines of the power cord. Refer to the
diagram.
Testing AC Motors
Disconnect the motor from the line by disconnecting the wires from the motor terminals or
opening the mains switch.
If the mains switch is opened, and the motor also has a motor-starter, then the starter must
be held in the ON position. With the mains switch opened, the measured resistance will
include the resistance of the motor wire and all other components between the motor and
the main switch. If a weakness is indicated, the motor and other components should be
checked individually. If the motor is disconnected at the motor terminals, connect one
meter lead to the grounded motor housing and the other lead to one of the motor leads.
Refer to diagram at below.
Motor
GND
Mains
Starter
Switch
Notes:
1. The STARTER must be in the ON position during the
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Model 380363 Version 2.0 July 2005