Hitachi SJ300 Series Derating Curves, SJ300 30 to 55 kW at 50 deg. C ambient, SJ300 1.5 to 22 kW at 50 deg. C ambient

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SJ300 Inverter

Derating Curves The maximum available inverter current output is limited by the carrier frequency and ambient temperature. The carrier frequency is the inverter’s internal power switching frequency, settable from 0.5 kHz to 12 kHz. Choosing a higher carrier frequency tends to decrease audible noise, but it also increases the internal heating of the inverter, thus decreasing (derating) the maximum current output capability. Ambient temperature is the temperature just outside the inverter housing—such as inside the control cabinet where the inverter is mounted. A higher ambient temperature decreases (derates) the inverter’s maximum current output capacity.

Use the following derating curves to help determine the optimal carrier frequency setting for your inverter, and to find the output current derating. Be sure to use the proper curve for your particular SJ300 inverter model number.

Started Getting

% of Drive’s Rated Amps

	SJ300 1.5 to 22 kW at 50 deg. C ambient
100%		004 to 150L
95%
90%
85%			185L
80%
75%
70%			220L
65%

0.5 2 4 6 8 10 12 14 15

Carrier Frequency (kHz)

% of Drive’s Rated Amps

SJ300 30 to 55 kW at 50 deg. C ambient

100%	550L	450L
95%
90%			370L
85%
80%			300L
75%			450L
70%
			550L
65%

0.5 2 4 6 8 10 12 14 15

Carrier Frequency (kHz)