Download Print this page

Husqvarna K7000 Workshop Manual page 20

Hide thumbs Also See for K7000:

Advertisement

7
Pin
K
A
B
C earth
Insulation testing of motor cables
Test pin A
Test pin B
1
2, 3 and 4
2
1, 3 and 4
3
1, 2 and 4
4
1, 2 and 3
20
TROUBLESHOOTING
X2
Cable
Red
Brown
White
Green/yellow
1
2
3
4
Thermistor
The thermistor is the motor's temperature monitor. It breaks the
current to the motor if the temperature is too high. A defective
thermistor may prevent the motor from starting. The thermistor is
connected to the display unit on the cutting machine, which issues
a warning if the motor temperature is too high.
The thermistor is integrated in the motor unit and cannot be
replaced separately.
The thermistor changes resistance according to temperature, which
can be measured with a multimeter. The machine must not have
been run recently: it must be at room temperature as shown in the
table. Measure at the contact X2, as shown in the photo at the top.
The adjacent table shows typical values, as well as minimums and
maximums.
If measured values are outside the tolerance ranges, the ther-
mistor is defective.
Cable between PP70 and K7000
Supply cables which have been "driven over" or abused are a
relatively common cause of interference. Carry out a visual check
of the outside of the cable for damage due to trapping. Also check
that the contact pin is undamaged.
The cables to the motor are examined first with connection
testing at both cable connections. This test shows whether there is
any cable failure. Insulation testing is then carried out, which
shows whether there is any damage to the cable insulation.
The signal cables, which work with low voltage, are examined
only with a multimeter for cable failure and insulation faults.
Motor cables – connection testing
Set the multimeter for connection testing with a buzzer.
Check that the three phase lines and the earth cable are connected
to the contacts on the cable ends. The labelling and cable colours
for the contact pins are shown in the adjacent photo (see also the
diagram on page 6).
Motor cables – insulation testing
Set the insulation tester to give a voltage of 1,000 volts.
It is suggested that the test pins should be connected to the
cable's connector at the motor side, X1. The arrangement for the
test may look like this:
– connect the first test pin to phase 1, the second test pin to phase
2, then to phase 3 and then to earth.
– connect the first test pin to phase 2, the second test pin to phase
1, then to phase 3 and then to earth.
– continue according to the same pattern until all cables have been
tested. See the adjacent table.
The insulation tester measures resistance during testing. The
measurement must indicate the maximum ohm value if the cabling
is fault-free. Poor insulation between the cables results in reduced
resistance.
The cable must be replaced if the connection test and insulation
test indicate broken cables or defective insulation.

Hide quick links:

Advertisement

loading