T&R PCU1 Series, Operating And Maintenance Manual

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Loading unit Metering range Range full scale
Approximate timer
start/stop current
None
Secondary Injection
10A 10A 2A
20A 20A 4A
100A 100A 20A
NLU5000
10% 500A 100A
50% 2500A 500A
100% 5000A 1000A
NLU2000
10% 200A 40A
50% 1000A 200A
100% 2000A 400A
NLU200
10% 20A 4A
50% 100A 20A
100% 200A 40A
2.3.1.6 Pulse Mode
Pulse mode may be used to generate high current pulses into the test object. The electronic
trips are disabled in pulse mode, and the output current is only limited by the circuit
impedance. This is useful for setting the current when testing thermal devices and testing
instantaneous trips.
2.3.2 General Procedure for Timing Tests
The procedure for timing is the same whether an external loading unit is connected or the
secondary current injection output from the PCU1 is used.
2.4.2.1 Connections
Ensure that the unit is switched off and the test object is isolated and grounded before making
any connections.
Connect the loading unit to the control unit as shown in figure 2.1. In the case of the
secondary injection output, make the connections shown in figure 2.2.
Set the ammeter range switch to one of the main output ranges (10%, 50% or 100%).
Connect the output cables to the desired output on the loading unit and to the test object.
Connect the supply lead to the mains and switch the main supply switch on. The display will
come on, showing the unit type and loading unit type whilst starting up.