The drive motor overload and overheat protection function complies with the National Electric Code (NEC) and the Canadian Electric Code, Part I (CEC).

Set the Motor Rated Current and L1-01 through L1-04 [Motor Overload Protection Select] correctly to enable motor overload and overheat protection.

Refer to the control method and set the motor rated current with E2-01 [Motor Rated Current (FLA)], E5-03 [PM Motor Rated Current (FLA)], or E9-06 [Motor Rated Current (FLA)].

E2-01: Motor Rated Current (FLA)

No.

(Hex.)

Name

Description

Default

(Range)

E2-01

(030E)

Motor Rated Current (FLA)

Sets the motor rated current in amps.

Determined by o2-04, C6-01

(10% to 200% of the drive rated current)

Note:
  • If E2-01 < E2-03 [Motor No-Load Current], the drive will detect oPE02 [Parameter Range Setting Error].

  • When the drive model changes, the display units for this parameter also change.

    • 0.01 A: B001 to B018, 2001 to 2042, 4001 to 4023

    • 0.1 A: 2056 to 2082, 4031 to 4060

The value set for E2-01 becomes the reference value for motor protection and the torque limit. Enter the motor rated current written on the motor nameplate. Auto-Tuning the drive will automatically set E2-01 to the value input for T1-04 [Motor Rated Current].

E5-03: Motor Rated Current (FLA)

No.

(Hex.)

Name

Description

Default

(Range)

E5-03

(032B)

Motor Rated Current (FLA)

Sets the PM motor rated current (FLA).

Determined by o2-04, C6-01

(10% to 200% of the drive rated current)

Note:

When the drive model changes, the display units for this parameter also change.

  • 0.01 A: B001 - B018, 2001 - 2042, 4001 - 4023

  • 0.1 A: 2056 - 2082, 4031 - 4060

The drive automatically sets E5-03 to the value input for T2-06 [PM Motor Rated Current] after you do these types of Auto-Tuning:

  • PM Motor Parameter Settings

  • PM Stationary Auto-Tuning

  • PM Stationary Tuning for Stator Resistance

  • PM Rotational Auto-Tuning

E9-06: Motor Rated Current (FLA)

No.

(Hex.)

Name

Description

Default

(Range)

E9-06

(11E9)

Motor Rated Current (FLA)

Sets the motor rated current in amps.

Determined by E9-01 and o2-04

(10% to 200% of the drive rated current)

Note:

When the drive model changes, the display units for this parameter also change.

  • 0.01 A: B001 to B018, 2001 to 2042, 4001 to 4023

  • 0.1 A: 2056 to 2082, 4031 to 4060

The setting value of E9-06 is the reference value for motor protection. Enter the motor rated current written on the motor nameplate. Auto-Tuning the drive will automatically set E9-06 to the value input for T4-07 [Motor Rated Current].

L1-01: Motor Overload (oL1) Protection

No.

(Hex.)

Name

Description

Default

(Range)

L1-01

(0480)

Motor Overload (oL1) Protection

Sets the motor overload protection with electronic thermal protectors.

Determined by A1-02

(0 - 6)

This parameter enables and disables the motor overload protection with electronic thermal protectors.

The cooling capability of the motor changes when the speed control range of the motor changes. Use an electronic thermal protector that aligns with the permitted load characteristics of the motor to select motor protection.

The electronic thermal protector of the drive uses these items to calculate motor overload tolerance and supply overload protection for the motor:

  • Output current

  • Output frequency

  • Motor thermal characteristics

  • Time characteristics

If the drive detects motor overload, the drive will trigger an oL1 [Motor Overload] and stop drive output.

Set H2-01 = 1F [Term MA/MB-MC Function Selection = Motor Overload Alarm (oL1)] to set a motor overload alarm. If the motor overload level is more than 90% of the oL1 detection level, the output terminal activates and triggers an overload alarm.

0
Disabled

Disable motor protection when motor overload protection is not necessary or when the drive is operating more than one motor.

Refer to Figure 1 for an example of the circuit configuration to connect more than one motor to one drive.

Figure 1. Protection Circuit Configuration to Connect More than One Motor to One Drive
1
Variable Torque

Use this setting for general-purpose motors with a 60 Hz base frequency.

The overload tolerance decreases as motor speed decreases because the cooling fan speed decreases and the ability of the motor to cool decreases in the low speed range.

The overload tolerance characteristics of the motor change the trigger point for the electronic thermal protector. This provides motor overheat protection from low speed to high speed across the full speed range.

 

Load Tolerance

Cooling Capability

Overload Characteristics

(at 100% motor load)

This motor is designed to operate with commercial line power. Operate at a 60 Hz base frequency to maximize the motor cooling ability.

If the motor operates at frequencies less than 60 Hz, the drive will detect oL1. The drive triggers a fault relay output and the motor coasts to stop.

2
Constant Torque 10:1 Speed Range

Use this setting for drive-dedicated motors with a speed range for constant torque of 1:10.

The speed control for this motor is 10% to 100% when at 100% load. Operating slower than 10% speed at 100% load will cause motor overload.

 

Load Tolerance

Cooling Capability

Overload Characteristics

(at 100% motor load)

This motor is designed to withstand increased temperatures during continuous operation in the low speed range (10% base frequency).

The motor operates continuously at 10% to 100% base frequency. Operating slower than 10% speed at 100% load will cause motor overload.

3
Constant Torque 100:1 SpeedRange

Use this setting for vector motors with a speed range for constant torque of 1:100.

The speed control for this motor is 1% to 100% when at 100% load. Operating slower than 1% speed at 100% load will cause motor overload.

 

Load Tolerance

Cooling Capability

Overload Characteristics

(at 100% motor load)

This motor is designed to withstand increased temperatures during continuous operation in the low speed range (1% base frequency).

The motor operates continuously at 1% to 100% base frequency. Operating slower than 1% speed at 100% load will cause motor overload.

4
PM Variable Torque

Use this setting for PM motors with derated torque characteristics.

The overload tolerance decreases as motor speed decreases because the cooling fan speed decreases and the ability of the motor to cool decreases in the low speed range.

The overload tolerance characteristics of the motor change the trigger point for the electronic thermal protector. This provides motor overheat protection from low speed to high speed across the full speed range.

 

Load Tolerance

Cooling Capability

Overload Characteristics

(at 100% motor load)

This motor is designed to withstand increased temperatures during continuous operation at rated speed and rated torque.

If the motor operates continuously at lower speed than rated rotation speed at more than 100% torque, the drive will detect oL1. The drive triggers a fault relay output and the motor coasts to stop.

5
PM Constant Torque

Use this setting with a PM motor for constant torque that has a speed range for constant torque of 1:500.

The speed control for this motor is 0.2% to 100% when at 100% load. Operating slower than 0.2% speed at 100% load will cause motor overload.

 

Load Tolerance

Cooling Capability

Overload Characteristics

(at 100% motor load)

This motor is designed to withstand increased temperatures during continuous operation in the low speed range (0.2% base frequency).

The motor operates continuously at 0.2% to 100% rated speed. Operating slower than 0.2% speed at 100% load will cause motor overload.

6
Variable Torque (50Hz)

Use this setting for general-purpose motors with a 50 Hz base frequency.

The overload tolerance decreases as motor speed decreases because the cooling fan speed decreases and the ability of the motor to cool decreases in the low speed range.

The overload tolerance characteristics of the motor change the trigger point for the electronic thermal protector. This provides motor overheat protection from low speed to high speed across the full speed range.

 

Load Tolerance

Cooling Capability

Overload Characteristics

(at 100% motor load)

This motor is designed to operate with commercial line power. Operate at a 50 Hz base frequency to maximize the motor cooling ability.

If the motor operates at frequencies less than commercial line power, the drive will detect oL1. The drive triggers a fault relay output and the motor coasts to stop.

L1-02: Motor Overload Protection Time

No.

(Hex.)

Name

Description

Default

(Range)

L1-02

(0481)

Motor Overload Protection Time

Sets the operation time for the electronic thermal protector of the drive to prevent damage to the motor. Usually it is not necessary to change this setting.

1.0 min

(0.1 - 5.0 min)

Set the overload tolerance time to the length of time that the motor can operate at 150% load from continuous operation at 100% load.

When the motor operates at 150% load continuously for one minute after continuous operation at 100% load (hot start), the default setting triggers the electronic thermal protector.

Figure 2 shows an example of the electronic thermal protector operation time. Motor overload protection operates in the range between a cold start and a hot start.

This example shows a general-purpose motor operating at the base frequency with L1-02 set to 1.0 min.

  • Cold start

    Shows the motor protection operation time characteristics when the overload occurs immediately after starting operation from a complete stop.

  • Hot start

    Shows the motor protection operation time characteristics when overload occurs from continuous operation below the motor rated current.

Figure 2. Protection Operation Time for a General-purpose Motor at Rated Output Frequency

L1-03: Motor Thermistor oH Alarm Select

No.

(Hex.)

Name

Description

Default

(Range)

L1-03

(0482)

Motor Thermistor oH Alarm Select

Sets drive operation when the PTC input signal entered into the drive is at the oH3 [Motor Overheat Alarm] detection level.

3

(0 - 3)

0
Ramp to Stop

The drive ramps the motor to stop in the deceleration time. The output terminal set for Fault [H2-01 to H2-03 = E] activates.

1
Coast to Stop

The output turns off and the motor coasts to stop. The output terminal set for Fault [H2-01 to H2-03 = E] activates.

2
Fast Stop

The drive stops the motor in the deceleration time set in C1-09 [Fast Stop Time]. The output terminal set for Fault [H2-01 to H2-03 = E] activates.

3
Alarm Only

The keypad shows oH3 and the drive continues operation. The output terminal set for Alarm [H2-01 to H2-03 = 10] activates.

L1-04: Motor Thermistor oH Fault Select

No.

(Hex.)

Name

Description

Default

(Range)

L1-04

(0483)

Motor Thermistor oH Fault Select

Sets the drive operation when the PTC input signal to the drive is at the oH4 [Motor Overheat Fault (PTC Input)] detection level.

1

(0 - 2)

0
Ramp to Stop

The drive ramps the motor to stop in the deceleration time. The output terminal set for Fault [H2-01 to H2-03 = E] activates.

1
Coast to Stop

The output turns off and the motor coasts to stop. The output terminal set for Fault [H2-01 to H2-03 = E] activates.

2
Fast Stop

The drive stops the motor in the deceleration time set in C1-09 [Fast Stop Time]. The output terminal set for Fault [H2-01 to H2-03 = E] activates.