Mitsubishi FR - S500 instruction manual Stall prevention

CAUTION

•* When "Operation not continued for OL signal output" is selected, the "OLT" alarm code (stopped by stall prevention) is displayed and operation stopped.

(Alarm stop display "")

•If the load is heavy, the lift is predetermined, or the acceleration/deceleration time is short, the stall prevention may be activated and the motor not stopped in the preset acceleration/deceleration time. Therefore, set optimum values to the Pr. 21 and stall prevention operation level.

•When the fast-response current limit has been set in Pr. 21 (factory setting), torque will not be provided at the Pr. 22 setting of 170% or higher. At this time, make setting so that the fast-response current limit is not activated.

•In vertical lift applications, make setting so that the fast-response current limit is not activated. Torque may not be produced, causing a gravity drop.

CAUTION

Always perform test operation.

Stall prevention operation performed during acceleration may increase the acceleration time.

Stall prevention operation performed during constant speed may cause sudden speed changes.

Stall prevention operation performed during deceleration may increase the deceleration time, increasing the deceleration distance.

2.3.13 Stall prevention

Set the output current level at which the output frequency will be adjusted to prevent the inverter from stopping due to overcurrent etc.

During high-speed operation above the rated motor frequency, acceleration may not be made because the motor current does not increase. To improve the operating characteristics of the motor in this case, the stall prevention level can be reduced in the high frequency region. This function is effective for performing operation up to the high speed range on a centrifugal separator etc. Normally, set 60Hz <50Hz> in Pr. 28 "stall prevention operation reduction starting frequency" and 100% in Pr. 23.

		Factory	Setting
Parameter	Name	Setting		Remarks
			Range
		<EC version>
22	Stall prevention operation	150%	0 to 200%	
	level
					Setting is
	Stall prevention operation		0 to	- - -: Pr. 22
					enabled
23	level compensation factor	- - -
			200%, - - -	equally	when
	at double speed
					Pr. 30 = "1".
28	Stall prevention operation	60Hz	0 to	
	reduction starting frequency	<50Hz>	120Hz

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