Braking Resistor Installation; Install A Braking Resistor: Erf-Type; Install A Braking Resistor Unit: Lkeb-Type - YASKAWA GA700 Technical Manual

2.18

Braking Resistor Installation

A braking resistor or braking resistor unit (dynamic braking option) helps stop the motor quickly and smoothly
when there is high load inertia. If you try to decelerate a motor in less time than usual for a coast to stop, the
motor will rotate faster than the synchronous speed that aligns with the set frequency. This will cause the motor to
become an induction generator. The inertia energy of the motor and regenerate to the drive and charge the drive
DC bus capacitor and increase the voltage. If the voltage is more than the overvoltage level, an ov [Overvoltage]
will occur. To prevent these overvoltage faults, a dynamic braking option is necessary.
WARNING!
Set L3-04 = 0 [Stall Prevention during Decel = Disabled] when operating the drive with:
• a regenerative converter
• regenerative unit
• braking unit
• braking resistor
• braking resistor unit.
Failure to obey could prevent the drive from stopping in the specified deceleration time and cause serious injury or death.
NOTICE: Do not allow unqualified personnel to use the product. Before you connect a dynamic braking option to the drive,
make sure that you review Braking Unit and Braking Resistor Unit Installation Manual TOBPC72060001. Failure to obey can
cause damage to the drive and braking circuit.
Note:
• Select the correct braking circuit size to dissipate the power that is necessary to decelerate the load in the correct time. Before you run
the drive, make sure that the braking circuit can dissipate the energy for the set deceleration time.
• To install a dynamic braking option, set L8-01 = 0 [3% ERF DB Resistor Protection = Disabled].
WARNING! Fire Hazard. The braking resistor connection terminals are B1 and B2. Do not connect braking resistors to other
terminals. Incorrect wiring connections could cause the braking resistor to overheat. Failure to obey can cause death or serious
injury by fire and damage to the drive and braking circuit.
NOTICE: Connect braking resistors to the drive as shown in the I/O wiring examples. Incorrectly wiring braking circuits can
cause damage to the drive or equipment.
To connect a Yaskawa ERF series braking resistor to the drive, set L8-01 = 1 [Enabled].
To use a non-ERF type braking resistor, connect a thermal overload relay between the drive and the braking
resistor, and set a circuit to de-energize the drive at the trip contacts of the thermal overload relay.
◆

Install a Braking Resistor: ERF-Type

Connect the braking resistor to drive models 2004 to 2021 and 4002 to 4012 as shown in
When you use a braking resistor, set L8-01 = 1 [3% ERF DB Resistor Protection = Enabled] and set one of the
MFDO parameters H2-01 to H2-03 = D [MFDO Function Select = Braking Resistor Fault]. Use a sequence that
uses MFDO to de-energize the drive.
◆

Install a Braking Resistor Unit: LKEB-Type

Connect the braking resistor unit as shown in
ERF DB Resistor Protection = Disabled].
Models 2004 to 2138 and 4002 to 4168 have a built-in braking transistor.
To prevent overheating the braking resistor unit, set a sequence to de-energize the drive at the trip contacts of the
thermal overload relay.
YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
Figure 2.120 Install a Braking Resistor: ERF-Type
Figure 2.121. To install a braking resistor unit, set L8-01 = 0 [3%

2.18 Braking Resistor Installation

Figure 2.120.
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