3.20.2 B-1# Brake Energy Funct.
Parameters to configure the dynamic braking functions in the drive. Note! This applies only to drives ordered with the optional factory installed brake chopper
option.
B-10 Brake Function
Option: Function:
[0] * Off No brake resistor is installed.
[1] Resistor brake A brake resistor is incorporated in the system, for dissipation of surplus brake energy as heat. Connecting
a brake resistor allows a higher DC link voltage during braking (generating operation). The Resistor brake
function is only active in frequency converters with an integral dynamic brake.
[2] AC brake Is selected to improve braking without using a brake resistor. This parameter controls an overmagneti-
zation of the motor when running with a generatoric load. This function can improve the OVC-function.
Increasing the electrical losses in the motor allows the OVC function to increase the braking torque without
exceeding the over voltage limit. Please note that AC brake is not as effective as dynamic breaking with
resistor.
AC brake is for Adv. Vector Control and flux mode in both open and closed loop.
B-11 Brake Resistor (ohm)
Range: Function:
50. Ohm* [5. - 65535. Ohm] Set the brake resistor value in Ohms. This value is used for monitoring the power to the brake resistor in
par. B-13 Braking Thermal Overload. This parameter is only active in frequency converters with an integral
dynamic brake.
If the selection is xxxx use this parameter. If the selection is xxx.xx, use par. C-23 Quick Stop Decel Time.
B-12 Brake Power Limit (kW)
Range: Function:
5.000 kW* [0.001 - 2000.000 kW] Set the monitoring limit of the brake power transmitted to the resistor.
The monitoring limit is a product of the maximum duty cycle (120 sec.) and the maximum power of the
brake resistor at that duty cycle. See the formula below.
For 200 - 240 V units:
P
resistor
=
390
2
×
dutytime
R
× 120
For 380 - 480 V units
P
resistor
=
778
2
×
dutytime
R
× 120
For 380 - 500 V units
P
resistor
=
810
2
×
dutytime
R
× 120
For 575 - 600 V units
P
resistor
=
943
2
×
dutytime
R
× 120
This parameter is only active in frequency converters with optional factory installed Brake Chopper..
B-13 Braking Thermal Overload
Option: Function:
This parameter is only active in frequency converters with an integral dynamic brake.
This parameter enables monitoring of the power to the brake resistor. The power is calculated on the
basis of the resistance (par. B-11 Brake Resistor (ohm)), the DC link voltage, and the resistor duty time.
[0] * Off No brake power monitoring required.
[1] Warning Activates a warning on the display when the power transmitted over 120 s exceeds 100% of the moni-
toring limit (par. B-12 Brake Power Limit (kW) ).
The warning disappears when the transmitted power falls below 80% of the monitoring limit.
[2] Trip Trips frequency converter and displays an alarm when the calculated power exceeds 100% of the mon-
itoring limit.
[3] Warning and trip
AF-650 GP Programming Guide
165
3
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