Connection Of Stand-Alone Option Units; Connection Of The Brake Resistor - Mitsubishi Electric 800 Series Instruction Manual

2.9

Connection of stand-alone option units

The inverter accepts a variety of stand-alone option units as required.
Incorrect connection will cause inverter damage or accident. Connect and operate the option unit carefully in accordance with
the Instruction Manual of the corresponding option unit.
2.9.1

Connection of the brake resistor

• When an inverter-driven motor is driven by a load or requires rapid deceleration, install an external brake resistor. Connect
the brake resistor to terminals P/+ and PR. (For the locations of terminals P/+ and PR, refer to the terminal block layout
(page 38).)
Use a brake resistor that has resistance and power consumption values higher than the following. Also, the brake resistor must
have a sufficient capacity to consume the regenerative power.
Voltage
Inverter
class
FR-E860-0.75K(0017)
FR-E860-1.5K(0027)
FR-E860-2.2K(0040)
575 V class
FR-E860-3.7K(0061)
FR-E860-5.5K(0090)
FR-E860-7.5K(0120)
Set parameters as follows:
• Pr.30 Regenerative function selection = "1"
• Set Pr.70 Special regenerative brake duty according to the amount and frequency of the regenerative driving, and make
sure that the resistor can consume the regenerative power properly. (Refer to the FR-E800 Instruction Manual (Function).)
• When the regenerative brake transistor is damaged, install a thermal relay as shown in the following sequence to prevent
overheat and burnout of the brake resistor. Properly select a thermal relay according to the regenerative driving frequency
or the rated power or resistance of the brake resistor.
<Example 1>
MC
Power
Supply
T
F
MC
ON OFF
OCR
Contact
MC
CAUTION
• If the resistor selection is incorrect, overcurrent may damage the inverter built-in brake transistor. Besides, the resistor
may be burned due to overheat.
• If the selection of the thermal relay is incorrect, the resistor may be burned due to overheat.
70
2. Installation and Wiring
2.9 Connection of stand-alone option units
Minimum resistance
(Ω)
350
300
260
190
140
100
Thermal relay
Inverter (OCR)
Brake resistor
R/L1 P/+
S/L2
T/L3
PR
Power consumption
(kW)
2.4
2.8
3.3
4.5
6.1
8.5
<Example 2>
R
Power
Supply
T
F
MC
ON OFF
MC
Thermal relay
MC Inverter
(OCR)
R/L1 P/+
S/L2
T/L3
PR
B
C
OCR
Contact
Brake resistor
R