Mitsubishi Electric C Series Handling And Maintenance page 31

(4) Connection of MDU breaker
1 Connections and installation 1 1
1 1
• Do not connect in reverse about line side and load side.
• Do not pull the cable which connects MDU and the circuit breaker over 15N. The cable may come off.
• When the trouble occurred, repair is performed pairing MDU and the circuit breaker.
• The cable which connects MDU and the circuit breaker, shall be kept the distance longer than 10cm from the heavy current
circuit. Fix the cable tightly near the connector to avoid the stress to the connector.
• The connector from the circuit breaker is insulated from inside of the circuit breaker.
The breaker usually works even if the cable is not connected with MDU.
But connect the cable early and correctly, because it may become cause of missing measuring.
• Supply the control power to L1 and L2 of MDU terminal. Fuses or MCCB shall be installed in control power curcuit.
Do not supply the control power of MDU from the main circuit.
• For function of alarm LED (PAL, OVER) on MDU and contact output (PAL, OAL), MDU and the circuit breaker must be
connected with the mutuality and the control power must be supplied to MDU and alarm contact output module.
• When MDU is used in 1 phase 2 wire, the connection is shown in figure 1.
The load side of phase No.1 is live part. It needs insulation processing.
Use the measurement data of l2, l3 and V2-3 lgnore the measurement data of l1, V1-3 and V3-1.
• When MDU is used in 1 phase 3 wire, the connection is shown in figure 2.
The neutral wire connects to phase No.2 of MDU.
If connect the neutral wire to phase No.1 or phase No.3 of MDU, then the measurement is not guaranteed.
Phase number
of MDU
Live part
Fig1. Connection of using in 1 phase 2wire. Fig2. Connection of using in 1 phase 3wire.
• Please note that three pole breaker with MDU cannot be used in three phase four line system.
When three pole breaker with MDU is used for three phase four line system, it becomes as shown in the table below.
Measuring items
Load current
Line voltage
Harmonics current
Electric power
Electric energy
Power factor
29
CAUTION
1 2 3
Line side
1 3 5
2
4
6
Load side
Load
Status
✕ N phase
Voltage phases
Voltage phases one another
✕ Voltage phases to N phase
✕ N phase
Voltage phases
✕
✕
✕
1 2
Phase number
200V
of MDU
100V
1 3
2
4
It is not possible to measure it because current
transformer is not in N phase.
It is not possible to measure it because voltage
transformer is not in N phase.
It is not possible to measure it because current
transformer is not in N phase.
It is not added in N phase to measure, because current
transformer and voltage transformer are not in N phase.
It is not added in N phase to measure, because current
transformer and voltage transformer are not in N phase.
It is not added in N phase to measure, because current
transformer and voltage transformer are not in N phase.
3
Neutral
100V
Line side
5
6
Load side
Reason