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Electronically Controlled B...
Figure 6.4 Drive Display with Bypass Start Time Delay Active
6.1.9 ECB Run Permissive
General Information
With run permissive active, the drive sends a run request
and waits for a remote response before notifying the
motor to start. The response indicates the system is safe to
operate. Run permissive operates from the LCP hand/off/
auto select in drive or bypass mode. Run permissive is
enabled by programming in the drive parameters.
Prior to Enabling Run Permissive
•
Complete the start-up procedure to verify motor
rotation direction in bypass is correct and that
the system is ready in all respects for continuous
full speed operation in bypass.
•
Verify that the drive is programmed for the run
permissive function. See the drive support
materials for programming the run permissive
function.
Operation
•
A start command can be initiated from local hand
start, serial communications, or a remote auto
start signal through digital drive input terminals.
•
In response to the start command, an output
request is sent from the programmable drive
relay to the external equipment (to activate a
valve or damper, for example).
•
When a return run signal on the digital input is
received, the motor is started in either drive or
bypass, depending upon which mode is active.
Vertical Bypass/Non Bypass Panel
Run Permissive Function Setup
Disable Run Permissive
6.1.10 ECB Overload
General Information
An overload device provides overcurrent protection for the
motor when running in bypass. The thermally activated
overload monitors motor current and trips to remove
power to the motor if a sustained overcurrent condition
exists. A Class 20 overload is standard with a variable
setting for motor current. Test and reset buttons are also
provided. In drive mode, the drive provides current sensing
and trip protection. Fuses provide quick action for high
over current conditions.
Prior to Enabling Overload
CAUTION
MOTOR DAMAGE!
Repeated attempts to reset overload can cause motor
damage. Correct the overload condition and let the
overload and motor return to normal operating
temperature before resetting. See motor manufacturer's
recommendations for time between start attempts. Failure
to correct the overload condition and let the motor return
to normal operating temperature could cause motor
damage.
Operation
Overloads and motors are both rated by class. The class is
defined by the NEC to determine the maximum time to
trip. A Class 20 overload, for example, has a typical trip
®
MG.13.A1.22 - VLT
is a registered Danfoss trademark
•
See the drive manual or support materials for
programming and wiring to the drive control
terminals.
•
Wire the output run request to the drive output
terminals selected, and program the terminals for
run request.
•
Wire the input run command to the drive input
terminals selected, and program the terminals for
run permissive.
•
Disable run permissive through the drive
parameters and terminal programming.
•
Verify that the overload current dial setting
matches the motor FLA rating on the motor
nameplate.
•
If the motor FLA is greater or less than the range
of the current dial, reconfirm that the motor HP
and voltage are within the option panel (and
drive) rating. If greater than the FLA rating,
replace the panel with one of a proper rating.
6
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