TSE DPT40-B, Owner'S Manual

Page: 406 / 472

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How to Measure Voltage
System voltage is measured at the magnets by connecting the
voltmeter to the two magnet lead wires at any brake. This may be
accomplished by using a pin probe inserted through the insulation
of the wires. The engine of the towing vehicle should be running
when checking the voltage so that a low battery will not affect the
readings.
Voltage in the system
should begin at 0 volts
and, as the controller bar
is slowly actuated, should
gradually increase to
about 12 volts. If the
controller does not
produce this voltage
control, consult your
controller manual.
The threshold voltage of a controller is the voltage applied to the
brakes when the controller first turns on. Lower threshold voltage
will provide for smoother braking. If the threshold voltage is too
high, the brakes may feel grabby and harsh.
How to Measure Amperage
System amperage is the current flowing in the system when all
the magnets are energized. The amperage will vary in proportion
to the voltage. The engine of the tow vehicle should be running
with the trailer connected when checking the trailer braking
system.
One place to measure system amperage is at the BLUE wire of
the controller which is the output to the brakes. The BLUE wire
must be disconnected and the ammeter put in series into the line.
System amperage draw should be as noted in the following table.
Make sure your ammeter has sufficient capacity and note polarity
to prevent damaging your ammeter.
Braking Systems - Electric
VOLTMETER