104
System Manual V2 – MOVITRAC® B
5
Explanation of the parameters
Parameters
7__
Control functions
All settings with regard to the fundamental control properties of the inverter are defined within parameter group 7__. This parameter
group comprises functions which the inverter automatically executes when they are activated.
70_
Operating mode 1 / 2
This parameter is used to set the basic operating mode of the inverter. Setting on the keypad.
VFC / V/f characteristic curve
: Default setting for asynchronous motors. Suitable for general applications, such as conveyor belts,
trolleys, and hoists with counterweight.
VFC & hoist
: The hoist function automatically provides all functions necessary for operating an unbalanced hoist. For safety reasons,
make sure to activate monitoring functions that prevent the drive from starting. Monitoring functions:
•
Monitoring the output current during the premagnetization phase
•
Avoiding sag when the brake is released
The unit detects the following incorrect configurations and displays them with the following faults:
•
2 or 3-phase motor phase interruption: F82 = Output open
•
Premagnetization time too short or incorrect motor/inverter combination: F81 = Error start condition
•
Motor phase failure due to active speed monitoring P500/501: F08 = Fault n-monitoring
Caution!
•
The control must be designed in such a way that the
direction of rotation of the drive can only be changed when it is at a
standstill
.
•
A single-phase motor phase failure cannot always be detected reliably.
•
SEW-EURODRIVE strongly recommends activating speed monitoring.
•
Prerequisite for correct performance of the hoist function: Motor brake controlled by the inverter.
•
Speed monitoring is set by changing parameters 500 / 502 and 501 / 503. The sagging of hoists cannot be avoided safely when
monitoring is deactivated or the delay time is set too long.
VFC & DC braking / V/f characteristic curve & DC braking
: DC braking means the asynchronous motor brakes by using current
injection. The motor brakes without braking resistor on the inverter. The following figure shows the braking torque profile when the
braking current is the same as the rated motor current.
During braking, the inverter injects a constant current with a rotating-
field frequency of 5 Hz. The braking torque = 0 at standstill. A greater
braking torque acts at a slower speed; the braking torque drops as
the speed increases. The braking time and consequently the duration
of the braking current depends on the load connected to the motor.
DC braking stops at a rotating-field frequency of the motor of 5 Hz.
The motor stops along the stop ramp. Rated motor current is used for
the current injection. In all cases, the inverter limits the current to
max. 125 %I
N
. See "Brake function" for information about the brake
control system.
Caution!
It is not possible to enable a directed stop or to observe a certain ramp using DC braking. The main purpose of DC braking is to
drastically reduce the time the motors need for coasting to a halt.
The following graphic shows the braking profile.
n
1
= Setpoint speed
[1] = Enable
t13 = Stop ramp
t
B
= Braking phase
No.
FBG
Name
Description
1
0
0
5 Hz
f
f
N
M/M
N
P
i
f
kVA
Hz
n
Summary of Contents for MOVITRAC MC07B0037-2A3-4-00
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