VLT
®
5000 Series
■ Parameters - Special functions
400 Brake function/overvoltage control
(BRAKE FUNCTION)
Value:
✭Off (OFF)
[0]
Resistor brake (RESISTOR)
[1]
Overvoltage control (OVERVOLTAGE CONTROL)
[2]
Overvoltage control and stop
(OVERVOLT CTRL. & STOP)
[3]
Function:
The factory setting is Off [0] for VLT 5001-5027
200-240 V, VLT 5001-5102 380-500 V and VLT
5001-5062 525-600 V. For VLT 5032-5052 200-240 V,
5122-5552 380-500 V, and VLT 5042-5602 525-690
V the factory setting is Overvoltage control [2].
Resistor brake [1] is used for programming the
frequency converter for connection of a brake resistor.
The connection of a brake resistor allows a
higher intermediate circuit voltage during braking
(generating operation).
The Resistor brake [1] function is only active in units
with an integral dynamic brake (SB and EB units).
Overvoltage control (excl. brake resistor) can
be selected as an alternative. This function
is available in all variants.
The function ensures that a trip can be avoided if the
intermediate circuit voltage increases. This is done
by increasing the output frequency to limit the voltage
from the intermediate circuit. This is a very useful
function, e.g. if the ramp-down time is too short, since
tripping of the frequency converter is avoided. In this
situation, the ramp-down time is extended.
NB!:
Pleasenotethattheramp-downtimeisextended
in the case of overvoltage control, which in
some applications may not be appropriate.
Description of choice:
Select Resistor brake [1] if a brake resistor
is part of the system.
Select Overvoltage control [2] if the overvoltage control
function is required in all cases - also if stop is pr
essed.
The frequency converter will n
ot stopinthecaseofa
stop command when the overvoltage control is active.
Select Overvoltage control and stop [3] if the
overvoltage control function is not required during
ramp-down after stop has been pressed.
Warning: If Overvoltage control [2] is used
at the same time as the supply voltage
to the frequency converter is close to or
above the maximum limit, there is a risk that the motor
frequency will increase and that, consequently, the
frequency converter will not stop the motor when
stop is pressed. If the supply voltage is higher than
264 V for 200-240 V units, higher than:
• 264 V for 200-240 V units
• 550 V for 380-500 V units
• 660 V for 525-600 V units
• 759 V for 525-690 V units
O
vervoltage control and stop [3] should be selected
so that the motor can be stopped.
401 Brake resistor, ohm
(BRAKE RES. (OHM))
Value:
Depends on the unit
✭ Depends on the unit
Function:
This parameter gives the ohmic value of the brake
resistor. This value is used for monitoring the
power to the brake resistor provided this function
has been selected in parameter 403.
Description of choice:
Set the present resistor value.
402 Brake power limit, kW
(BR.POWER. LIM.KW)
Value:
Depends on the unit
✭ Depends on the unit
Function:
This parameter gives the monitoring limit of the
power transmitted to the brake resistor.
Description of choice:
The monitoring limit is determined as a product of
the maximum duty cycle (120 sec.) that will occur
and the maximum power of the brake resistor at that
duty cycle according to the following formula.
For 200 - 240 V units: P =
For 380 - 500 V units: P =
For 525 - 600 V units: P =
For 525 - 690 V units: P =
✭ = factory setting. () = display text [] = value for use in communication via serial communication port
MG.51.A9.02 - VLT is a registered Danfoss trademark
138
To Next Page
Loading...
Need help?
General