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Special Procedures
General
This section contains a number of useful tips that should be noted when working with inductive loads.
Inductive loads include devices such as transformers, coils, ballasts, wire-wound resistors, magnets and
motors. These types of devices require special consideration as described below.
Connections and Settling Time
When connecting the cables to the inductive load, care should be taken not to draw an arc. The Test
Current should be turned off and the cables positively clamped onto the load before applying current.
When measuring highly inductive loads the settling time of the ohmmeter is determined by the
compliance voltage of the current source. Typically, the compliance voltage of a 4300C in the Charging
Inductor mode is in excess of 20V. Thus, with an inductor of 1000 Henries (an extremely large transformer)
the unit will take approximately 10 minutes to settle. During settling, the unit will display overload and
should be ignored until the Charging Inductor indicator is extinguished.
The actual equation for determining settling time is as follows:
T = (L x I)/V
Where:
T = settling time in seconds
L = inductance in Henries
I = current range (in amps)
V = compliance voltage of 4300C (20V)
Note that the higher the test current, the longer the settling time.
Summary of Contents for 4300C
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