Power Section Check - Magnetek Impulse G+ series 4 Instruction Manual

Power Section Check

Do NOT touch any circuit components while AC main power is on or immediately after the
main AC power is disconnected from the unit. You must wait until the red "CHARGE" lamp is
extinguished. It may take as long as 10 minutes for the charge on the main DC bus capacitors
to drop to a safe level. Failure to adhere to this warning could result in serious injury.
Power Off Checks
To perform a power section check, remove the drive's main and control wiring from the terminal
strips. Obtain reading as specified in the table on the next, and ensure that the reading falls within
the normal reading range.
Test equipment - Analog Ohmmeter set R x 1 scale or digital multimeter set to the diode.
Device
Input Rectifier
Bridge *1
Bus Capacitors
Pre-charge
Resistor
Output
Transistors
*2
*3
Braking Diode
1. "+" could be any one of three (+) terminals which are labeled as
2. If the bus fuse is blown you must install a jumper across the fuse terminals to get accurate resistance measurements.
3. If the pre-charge resistor is open, you will read infinite W between + and any output terminal unless you install a temporary jumper across the
resistor.
IMPULSE®•G+ & VG+ Series 4 Instruction Manual – February 2017
6-30
VOM (on RX1 Scale)
Positive Lead Negative Lead
L1
L2
L3
– L1
– L2
– L3
L1
L2
L3
+ L1
+ L2
+ L3
+
– Across the Resistors
T1
T2
T3
– T1
– T2
– T3
T1
T2
T3
+ T1
+ T2
+ T3
B2 B1
B1 B2
B2
– B2
WA R N I N G
Normal Reading
(Analog Meter)
+
+
+
7–100
–
–
–
Infinite 
Observe gradually
–
increasing resistance
100  or less
+
+
+
7-100 
–
–
–
Infinite 
10 
Infinite 
Infinite 
–
Infinite 
  
1, 2, and 3.
Normal Reading
(Digital Meter)
Approximately 0.5 V
OL Displayed
Observe gradually
increasing voltage to OL
–
Approximately 0.5V
OL Displayed
0.5 V
OL Displayed
OL Displayed
0.5 V