Lenze AC Tech M3103S Installation & Operation Manual page 52

Refer to the table below:
MODEL M3100
240 / 120 Vac
24 VOLTS
DC TIME
13
This parameter determines the length of time that the DC braking voltage is applied to the
motor . DC TIME should be set to the lowest value that provides satisfactory operation
in order to minimize motor heating .
NOTE:
If this parameter is set to 999 .9 seconds (the maximum value), the DC braking
will be continuous . If it is set to .0 seconds, it is disabled .
DYN BRAKE (DYNAMIC BRAkE)
14
This parameter enables the dynamic braking circuit . Set this parameter to ON only if the
optional dynamic braking circuit board and resistors are installed .
Dynamic braking is used in applications where high-inertia loads need to be decelerated
quickly . When this is attempted, the motor regenerates voltage back into the drive, causing
the DC bus voltage to rise, eventually resulting in a HI VOLTS fault . With the dynamic
braking option, the DC bus voltage is monitored, and when it reaches a certain level, a
transistor is switched on that connects an external resistor bank across the DC bus . This
allows the regenerated energy from the motor to be dissipated through the resistors as
heat, which keeps the DC bus voltage below the trip level .
CURRENT
16
This parameter sets the maximum allowable output current of the drive, which also
determines the torque capability of the motor . For most applications, CURRENT is left
at the maximum setting, which is 150% or 180% (of the drive's output current rating),
depending on whether the input voltage is low or high (refer to Parameter 0 - LINE VOLTS) .
Regardless of the CURRENT setting, the drive is capable of delivering a maximum of
150% current for one minute, and 180% current for approximately 30 seconds, before
tripping into an OVERLOAD fault . Refer to Parameter 17 – MOTOR OL .
The drive will enter current limit when the load demands more current than the drive can
deliver, which results in a loss of synchronization between the drive and the motor . To
correct this condition, the drive will enter FREQUENCY FOLDBACk, which commands
the drive to decelerate in order to reduce the output current and regain synchronization
with the motor . When the overcurrent condition passes, the drive will return to normal
operation and accelerate back to the speed setpoint . However, if FREQUENCY
FOLDBACk cannot correct the condition and the drive remains in current limit for too
long, it will trip on an OVERLOAD fault . If the drive enters current limit while accelerating,
the time required to reach the speed setpoint will be longer than the time programmed
into ACCEL (Parameter 8) .
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MAXIMUM DC BRAKE VOLTAGE
MODEL M3200
240 / 200 Vac
24 VOLTS
(DC BRAkE TIME)
(CURRENT LIMIT)
M301L
MODEL M3400
480 / 400 Vac
48 VOLTS
MODEL M3500
590 / 480 Vac
59 VOLTS