Hitachi L2002 Overload Restriction

3–37

L2002 Inverter

Overload Restriction

If the inverter’s output current exceeds a	Motor
preset current level you specify during
	Current
acceleration or constant speed, the overload
				Restriction area
restriction feature automatically reduces the		B022
output frequency to restrict the overload.	0
This feature does not generate an alarm or
					t
trip event. You can instruct the inverter to
apply overload restriction only during	Output
constant speed, thus allowing higher
	frequency
currents for acceleration. Or, you may use
the same threshold for both acceleration and	0
constant speed.
					t
			B023

When the inverter detects an overload, it

must decelerate the motor to reduce the current until it is less than the threshold. You can choose the rate of deceleration that the inverter uses to lower the output current.

The overload restriction level can be set to a constant or to a variable (analog input). For constant values, use B028/B228 = 00 to select parameters B022/B222. For a variable overload restriction level, use B028/B228 = 01 to select analog voltage input terminals [O]–[L]. In this case, parameters A013 and A014 set the start and end points for the linear range of the graph as shown in the graphs below.

150%

150%

Overload

Overload

restriction

restriction

level

level

10%

10%

0V

10V

0V

2

8

10V

[O]–[L] input

[O]–[L] input

A013 = 0

A014 = 100

A013 = 20

A014

= 80

When using the analog input method to set the overload restriction (B028/B228 = 01), the inverter does not read settings B022/B222 Overload Restriction Level. Instead, the inverter writes the analog input value (in Ampere units) to parameters B022/B222. In this way, you can monitor the effective overload restriction value (in Amperes) in real time. However, you cannot store the value to B022/B222. If you use the second motor function, the inverter displays “void” for either B022 or B222 if the parameter’s corresponding motor is not selected via Set or Special Set functions.

Input	State	B022 monitor display	B222 monitor display	Units
[SET] or [S-ST]	OFF	[O] analog input value	void	A
	ON	void	[O] analog input value	A

Parameters Drive Configuring