Yaskawa Varispeed-656 DC5 - Manual (Page 68)

E-58
Appendix B PRECAUTIONS ON VS-656DC5 APPLICATION
„ Total Load Capacity
The total load capacity must be less than the VS-656DC5 rated output capacity according to
the motoring side capacity and the regenerating side capacity that are driven at the same
time.
Note: When the imbalance ratio between the phases exceeds 2%, use the
VS-656DC5 of one frame larger.
The imbalance ratio between the phases can be calculated as follows:
„ Input AC Reactor
Input AC reactors each of which corresponds to each capacity of the VS-656DC5, (consider-
ing saturation current and thermal items) are necessary for the PWM converter VS-656DC5.
Use the proper reactors for applications.
„ VS-656DC5 Power OFF and Harmonics Filter
Set up sequence that opens after the VS-656DC5 operation is stopped at the VS-656DC5
power suply side. Be sure to attach the specified harmonics filter to reduce the influence on
other devices caused by surge voltage at open that unexpectedly occurs during run.
„ Installation on the VS-656DC5 Output (DC) Side
If installing a circuit breaker or a magnetic contactor on the VS-656DC5 output (DC) side to
shut down the power supply in an emergency, observe the following precautions.
• Be sure to confirm that the charge lamps on the VS-656DC5 and the Inverter are not lit,
and then turn on the circuit breaker or contactor.
If the circuit breaker or contactor is turned on while power is supplied to the VS-
656DC5 and the Inverter, an overcurrent may occur and damage the circuit breaker or
contactor.
• Be sure to confirm that the circuit breaker or contactor is turned on before the power is
turned on for the VS-656DC5.
P
out
: VS-656DC5 rated output HP (kW)
P
M1
to P
MN
: Motor output HP (kW)
η
M
: Motor efficiency 0.9 *
η
INV
: Inverter efficiency 0.95 *
* When a motor less than 10HP (7.5 kW) is used,
set the motor efficiency and inverter efficiency
to 0.85 and 0.9, respectively.
PoutH (kW) ≥ (P
M1
+ xxx +P
MN
) - η
INV
× η
M
(P
M1
’ + xxx +P
MN
’)
η
INV
× η
M
1
Motoring Side Capacity Regenerating Side Capacity
Imbalance ratio between phases [%] = × 67
Max.voltage - Min.voltage
3-phase average voltage