Mitsubishi Electric 700 Series Instruction Manual page 129

Selection and protection of a motor
(2) Set two different electronic thermal O/L relays (Pr. 51)
Use this function when running two motors of different rated currents individually by a single inverter. (When running two
motors together, use external thermal relays.)
Set the rated current of the second motor to Pr. 51.
When the RT signal is ON, thermal protection is provided based on the Pr. 51 setting.
Pr. 450 Pr. 9
Second applied Electronic
motor thermal O/L relay
9999 0
9999 Other than 0
Other than 9999 0
Other than 9999 Other than 0
... Output current value is used to perform integration processing.
Δ .... Output current is assumed as 0A to perform integration processing. (cooling processing)
× .... Electronic thermal relay function is not activated.
REMARKS
The RT signal acts as the second function selection signal and makes the other second functions valid. (Refer to page 143)
(3) Electronic thermal relay function prealarm (TH)
100%: Electronic thermal O/L relay alarm operation value
Electronic thermal
relay function
operation level
Electronic thermal
Not
relay function
displayed
prealarm (TH)
Parameters referred to
Pr. 71 Applied motor
Pr. 72 PWM frequency selection
124
Pr.51
Second electronic
First
thermal O/L relay motor
9999
0
0.01 to 500
9999
0
0.01 to 500
9999
0
0.01 to 500
9999
0
0.01 to 500
100%
85%
Not
Displayed Displayed
displayed
Refer to page 125
Refer to page 163
RT = OFF RT = ON
Second First Second
motor motor motor
× × × ×
× × × ×
× Δ ×
× ×
× Δ ×
Δ Δ
× × × ×
× × × ×
× Δ ×
Δ Δ
× Δ ×
Δ Δ
The electronic thermal relay function prealarm (TH) is
displayed when the electronic thermal O/L relay
cumulative value reaches 85% of the level set in Pr. 9 or
Pr. 51. If it reaches 100% of the Pr. 9 Electronic thermal
O/L relay setting, a motor overload trip (E.THM/E.THT)
occurs.
Time