Rockwell Automation 8720MC 8720MC Regenerative Power Supply User Manual User Manual
Page 48
Wiring
4-10
If a totally external resistor network is used as shown in Figure 4.5,
the calculated wattage, [W] = 17,000
x
C farads, is divided in half
to size the precharge and discharge resistors.
required. Table 4.5 provides the minimum resistance value for the
external precharge resistor, 30 ohms in the case of the RPS027 and
20 ohms in the case of the RPS065. The wattage [W] is determined
by the equation presented above. Connect the external precharge
resistor to terminals PR1 and PR2 on terminal block TB2.
Terminal PR3 should be left open. See Chapter 2, Figure 2.1 under
"Terminal Blocks on the Main Circuit". The Precharge/Discharge
Time (F.014) may require a larger value to accommodate the
increased precharge time. The Wattage of Precharge/Discharge
Resistor (F.015) should also be increased to the external precharge
resistor wattage.
External circuit case
In the case of the RPS027 if the total capacitance is above 55,000
µ
f
but less than 82,500
µ
f an external precharge resistor connected as
shown in Figure 4.5 must be provided. In the case of the RPS065 if
the total capacitance is above 110,000
µ
f but less than 220,000
µ
f an
external resistor connected as shown in Figure 4.5 must be
provided. Table 4.5 provides the minimum resistance value for the
external precharge resistor, 10 ohms in the case of the RPS027 and
4.7 ohms in the case of the RPS065. The wattage [W] is
determined by the equation presented above.
Figure 4.5
Example of Wiring when Precharge/Discharge Circuit of the 8720MC-RPS027 or
8720MC-RPS065 is configured with an External Circuit
Precharge/
Discharge
Resistor
Power for Sequence Circuit
<3
<2
<1
1> Remove the jumper between PR2 and PR3.
2> Because driving current of sequence input signals is 5mA and below,
use a contact of which minimum applicable load is 5mA and below.
3> Use the reactor in maximum surrounding air temperature of
55 degree C (131 degree F) and below.
Main
Power
MC
MC
MC
MC
PWR
PWR
RCPB
CN15
CN5
CN17
PIFS
DIS
PR2
PRX
PR3
PR1
PR
PR
Fuse
1
DC Output
Fuse
Fuse
G
L
3AUX
L
2AUX
L
1AUX
L
3
L
2
L
1
TB2
MC1
MC2
PRX
PWR
MC
MC
PR3
PR2
PR1
TB1
E
TB1
DISR
DIS
DIS
N
P
24V
BDSR
Harmonic Filter
MC
DIS
PRX
DC Contactor
Varistor
Reactor