Mitsubishi Electronics FR-S500 Setting, Selection and protection of a motor Pr. 9 , Pr. 71 , H7

Explanation of functions (parameters)

2.3.6Selection and protection of a motor (Pr. 9 , Pr. 71 , H7 )

Set the motor used and protect the motor from overheat.

This feature provides the optimum protective characteristics, including reduced motor cooling capability, at low speed.

POINT

•When using the Mitsubishi constant-torque motor

Set "1" in Pr. 71 for V/F control or automatic torque boost control.

The electronic thermal relay function is set to the thermal characteristic of the constant-torque motor.

•When you selected the Mitsubishi constant-torque motor, the values of the following parameters are automatically changed. (only when the setting values of those parameters are at factory setting)

Pr. 0 "torque boost", Pr. 12 "DC injection brake voltage"

Para	Name	Factory	Setting	Remarks
meter		Setting	Range
9	Electronic thermal	Rated output	0 to 50A
	O/L relay	current
71	Applied motor	0	0, 1,		Setting is
			100, 101		enabled
					when
H7	Second electronic	- - -	0 to 50A,	- - -: Without second electronic
(559)	thermal O/L relay		- - -	thermal relay function	Pr. 30 = "1"

•The parameter number in parentheses is the one for use with the parameter unit (FR-PU04).

<Setting>

•Refer to the following list and set Pr. 71 according to the motor used.

Setting "100 or 101" changes thermal characteristic of the electronic thermal relay function to thermal characteristics of a Mitsubishi constant-torque motor when the RT signal is ON.

Pr. 71 Setting	Thermal Characteristic of the ElectronicThermal Relay Function
0, 100	Thermal characteristics of a standard motor
1, 101	Thermal characteristics of a Mitsubishi constant-torque motor
	(This provides a 100% continuous torque characteristic in the low-speed region.)

•Set the rated current [A] of the motor in Pr. 9. (Normally set the rated current at 50Hz.)

•Setting "0" in Pr. 9 disables electronic thermal relay function (motor protective function). (The protective function of the inverter is activated.)

•When setting second electronic thermal relay function, set the motor rated current value in the additional parameter H7. The second electronic thermal relay function is valid when the RT signal is on. (When the RT signal is on, other second functions (Pr.44 to Pr.47) are also selected.)

CAUTION

•When two or more motors are connected to the inverter, they cannot be protected by the electronic thermal relay function. Install an external thermal relay to each motor.

•When a difference between the inverter and motor capacities is large and the setting becomes less than half amount of the inverter rated current, the protective characteristics of the electronic thermal relay function will be deteriorated. In this case, use an external thermal relay.

•A special motor cannot be protected by the electronic thermal relay function.

Use an external thermal relay.

2

FUNCTIONS

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