Motor Overload Protection - Omron VARISPEED L7 Manual

Adjusting the Torque Limit Integral Time (L7-06)
In Open Loop Vector control, during constant speed the limit function works with an integral control part (dur-
ing acceleration and deceleration just a P-control is used). Normally there is no need to change this setting.
Increase the setting if vibrations or short cycle oscillations occur when the motor is running at the set
•
torque limit
Decrease the setting if long cycle oscillations occur when the motor is running at the set torque limit.
•
Enabling the Torque Limit Integral Operation during Accel./Decel. (L7-07)
In Open Loop Vector control an integral operation can be applied to the torque limit function (P-control is
standard). This improves the torque limit responsiveness and smoothes the torque limit operation. To enable
the integral operation set parameter L7-07 to 1. The integral time set in parameter L7-07 is used.
Setting Precautions
When the output torque reaches the torque limit, control and compensation of the motor speed is disabled
•
to prevent the output torque from exceeding the torque limit. The torque limit has the priority.
The torque limit accuracy is ±5% at an output frequency of 10 Hz or above. When output frequency is
•
lower than 10 Hz, the accuracy is lower.

Motor Overload Protection

The motor can be protected from overload using the built-in electronic thermal overload relay function.
Related Parameters
6
Parameter
No.
E2-01
E4-01
E5-02
L1-01
L1-02
*1. Factory settings depend on Inverter capacity. (The given value is for a 400 V Class Inverter with 3.7 kW.)
Multi-Function Outputs (H2-01 to H2-03)
Set
Value
1F Motor overload (OL1, including OH3) pre-alarm (ON: 90% or more of the detection level)
Setting the Motor Rated Current (E2-01, E4-01 or E5-02))
Set the rated current value on the motor nameplate in parameters E2-01 (for motor 1), E4-01 (for motor 2) or
E5-02 (PM motor). This set value is the base current for the internal thermal overload calculation.
44
6-
Name
Motor 1 rated current
Motor 2 rated current
PM Motor rated current
Motor protection selection
Motor protection time constant
Change
Factory
during
Setting
Operation
*1
7.00 A
*1
7.00 A
*1
7.31 A
1
1.0 min
Function
Control Methods
Open Closed
V/f Loop Loop
Vector Vector
No Q Q Q
No Q Q Q
No Q Q Q
No Q Q Q
No A A A
Control Methods
Open Closed
V/f Loop Loop
Vector Vector
Yes Yes
Closed
Loop
Vector
(PM)
-
-
-
A
-
Closed
Loop
Vector
(PM)
Yes Yes