Checking The Motor And Power Supply - Brother S-7200A Service Manual

9. CONTROL BOX AND MOTOR

9-4. Checking the motor and power supply

Turn off the power switch and disconnect the power cord from the wall outlet before carrying out these operations.
The machine may operate if the treadle is depressed by mistake, which could result in injury.
If the power switch needs to be left on when carrying out some adjustment, be extremely careful to observe all
safety precautions.
<Motor>
Ｕ phase
<Power switch>
<100 V type>
Ground wire
<200 V type>
45
CAUTION
2329M
Ｗ phase
Ｖ phase
1883M
1884M
1. Disconnect the motor connector 4P (1) from the control
box.
2. Measure the resistance of the motor connector (1) using
an ohmmeter in the x 1 range.
If the value is as shown in the table below, the connector
is normal.
Between 2–3
Between 3–4
Between 4–2
1. Disconnect the power supply connector 6P (2) from the
control box.
2. Turn on the power switch.
3. Measure the voltage at the power supply connector (2)
using the AC voltage range of a multimeter, and check
that the voltage is within the allowable range for the
specified voltage rating.
100 V type (100–120 V)
Measure the AC voltage between terminals 2–3.
200 V type (200–240 V)
[A] For three-phase
Measure the AC voltage between terminals 4–5,
5–6 and 6–4.
[B] For single-phase
Measure the AC voltage between terminals 4–6.
S-7200A
Approx. 1.6Ω