Mitsubishi Electric FR-A800 Plus Series Installation Manuallines page 65

A.2.5 Motor overload protection
When using the electronic thermal relay function as motor overload protection, set the rated motor current to Pr. 9 "Electronic
thermal O/L relay".
Electronic thermal relay function operation characteristic
Pr. 9 = 50 % setting of
*1, *2
inverter rating
70
30Hz
*3
or more
20Hz
60
10Hz
6Hz
0.5Hz
50
240
180
120
60
105%
52.5%
50
Inverter output current [%]
(% to the inverter rated current)
CAUTION
O The internal accumulated heat value of the electronic thermal relay function is reset by inverter power reset and reset signal
input. Avoid unnecessary reset and power-OFF.
O When using multiple motors with one inverter, or using a multi-pole motor or a specialized motor, provide an external thermal
relay (OCR) between the inverter and motor. And for the setting of the thermal relay, add the line-to line leakage current to the
current value on the motor rating plate (details in "FR-A800 Instruction Manual (Detailed)").
O For low-speed operation where the cooling capability of the motor reduces, it is recommended to use a thermal protector or
thermistor-incorporated motor.
O When the difference between the inverter and motor capacities is large and the setting is small, the protective characteristics of
the electronic thermal relay function will be deteriorated. In this case, use an external thermal relay.
O A special motor cannot be protected by the electronic thermal relay function. Use an external thermal relay.
O Set Pr. 9 = "0" for vector-control-dedicated motors (SF-V5RU) because they are equipped with thermal protectors.
O Motor over temperature sensing is not provided by the drive.
A.3 SERIAL number check
The SERIAL number can be checked on the inverter rating plate or package. (Refer to page 1.)
Rating plate example
l p
Symbol Year
The SERIAL consists of one symbol, two characters indicating production year and month, and six characters indicating control
number. The last digit of the production year is indicated as the Year, and the Month is indicated by 1 to 9, X (October), Y
(November), or Z (December).
A.4 Instructions for EAC
The product certified in compliance with the Eurasian Conformity has the EAC marking.
Pr. 9 = 100 % setting of
*2
inverter rating
*3
30Hz
or more
O Operation region
20Hz
Region on the right of
10Hz
characteristic curve
O Non-operation region
6Hz
Region on the left of
characteristic curve
0.5Hz
Characteristic when electronic
thermal relay function for motor
protection is turned OFF
(Pr. 9 = 0 (A))
Region for
transistor
*4
protection
100
150 230
p pppppp
Month Control number
SERIAL
This function detects the overload (overheat) of the motor,
stops the operation of the inverter's output transistor, and
stops the output. (The operation characteristic is shown
on the left.)
When using the Mitsubishi Electric constant-torque motor
set one of "1", "13" to "16", "50", "53", "54" in Pr. 71. For FR-
A842 models set one of "1", "13" to "16" in Pr. 71. This pro-
vides a 100 % continuous torque characteristic in the low-
speed range. Set the rated current of the motor in Pr. 9.
*1
When 50% of the inverter rated output current (current value)
is set in Pr. 9.
*2
The % value denotes the percentage to the inverter rated
output current. It is not the percentage to the motor rated
current.
*3
When you set the electronic thermal relay function dedicated
to the Mitsubishi Electric constant-torque motor, this
characteristic curve applies to operation at 6 Hz or higher.
*4
Transistor protection is activated depending on the
temperature of the heatsink. The protection may be activated
even with less than 150% depending on the operating
conditions.
APPENDIX
59