Hitachi SJ300 Series Free Thermal Characteristic, Constant Torque Characteristic

3–32

Configuring Drive Parameters

“B” Group: Fine-Tuning Functions

Constant Torque Characteristic – Selecting the constant torque characteristic for the example motor gives the curves below. At 2.5 Hz, the output current is reduced by a factor of 0.9 for given trip times.

Trip current				Trip
reduction				time (s)
factor
x 1.0				60
x 0.9
x 0.8				0.5
0
			Hz	0				A
2.5	5	60		47.8		62.1	82.8
				104%		135%	180%
					Reduced trip current at 2.5 Hz

Free Thermal Characteristic - It is possible to set the electronic thermal characteristic using a free-form curve defined by three data points, according to the table below.

Function	Name	Description	Range
Code
B015 / B017 /	Free-setting electronic	Data point coordinates for Hz axis	0 to 400Hz
B019	thermal frequency 1, 2, 3	(horizontal) in the free-form curve
B016 / B018 /	Free setting electronic	Data point coordinates for Ampere	0.0 = (disable)
B020	thermal current 1, 2, 3	axis (vertical) in the free-form curve	0.1 to 1000.

The left graph below shows the region for possible free-setting curves. The right graph below shows an example curve defined by three data points specified by B015 – B020.

Trip current				Output
reduction
				current (A)
factor
x 1.0
					B020
x 0.8	Setting range				B018
					B016						Hz
0				Hz	0
										max. freq.
5		Output freq.	400			B015	B017	B019	Ax04

Suppose the electronic thermal setting (B012) is set to 44 Amperes. The left graph below shows the effect of the free setting torque characteristic curve. For example, at (B017) Hz, the output current level to cause overheating in a fixed time period is reduced by a factor of (B018). The right graph below shows the reduced trip current levels in those conditions for given trip times.

Trip

time (s)

60			(x) = B018 value x 116%
			(y) = B018 value x 120%
0.5			(z) = B018 value x 150%
0			A
	(x) (y)	(z)

Reduced trip current at (B017) Hz