Using the RT3-100L
16
9. Using the RT3-100L
Some RT3-100P and RT3-100L controls differ, but the functions of both units are the same. The
RT3-100L can be used immediately upon receipt. When Continuous mode is selected, you must
set the Test switch to Off to stop test current flow. Follow these steps to use the RT3-100L.
1. Set the RT3-100L power switch to Off.
2. Connect the AC power, potential, and current leads to the RT3-100L connectors.
3. Connect the unit to an AC power source.
4. Connect the current clamps to the exposed metal portions of the equipment to be tested.
Connect the potential clips to the same metal as the current clamps. Make sure the
potential clips are between the current clamps and the load under test.
WARNING
: If testing a circuit breaker, one side of the power circuit breaker must be
grounded prior to connecting the RT3-100. Refer to
Circuit Breaker Testing
.
5. Set the meter range switch to the desired position.
6. Power on the RT3-100L.
7. Set the Test switch to either Momentary or Continuous. For momentary operation, hold
the switch for at least one second. NOTE: Use the Momentary mode for purely resistive
load testing. Use the Continuous mode for inductive loads such as circuit breakers with
current transformers.
8. In about one second (for resistive load) or after the reading has settled (for inductive
load), the meter displays the resistance of the equipment under test. This reading is
displayed until either the On/Off switch is set to Off or a new test is initiated.
NOTE: A cool down circuit inhibits subsequent testing for a few seconds. After cool
down, you make take another reading.
9. Set the power switch to Off after completing all tests.
WARNING
: Because of the energy stored in a magnetic field, high voltages can be
generated when the test connections are opened. Take the following precautions when
disconnecting the leads after testing inductive loads.
10. Verify the On/Off switch is set to Off. Do not touch the winding terminals.
11. Using one hand only, disconnect the potential (sense) leads, one at a time, then
disconnect the current (power) leads, also one at a time.
NOTE: Under normal operation, the Error LED lights at the start of current flow, then goes
out. If the Error LED remains on, this indicates insufficient current through the load, and the
reading should be considered invalid. Check that the current lead connections are secure. If,
at any time, the accuracy of the instrument is in question, test the instrument using the 1000
microhm test shunt provided.
After it displays the results of the test, the RT3-100L is ready for another reading. Several
readings may be taken in quick succession without affecting instrument accuracy.