Emb Run Permissive; Emb Overload - Danfoss VLT FC Series Operating Instructions Manual

Electromechanical Bypass (E...

5.1.4 EMB Run Permissive

General information
Run permissive allows a remote signal to notify the drive
to start, indicating the system is safe to operate. Run
permissive works in drive or bypass mode. Run permissive
is disabled by factory default when ordered by a jumper
wire on connector X58 between terminals 1 and 2.
Before 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 from local hand start on
the LCP or a remote auto start signal through
digital input connector X55, terminals 3 and 4, or
the serial communications input.
•
In response to a start command, an output
request is sent from X58 terminals 1 and 2 to the
external equipment (to activate a valve or
damper, for example).
•
When a return run signal on X55 terminals 1 and
2 is received, the motor is started in either drive
or bypass mode, depending upon the bypass
switch position.
Run permissive function setup
•
Remove factory-installed jumper wire on
connector X55, terminals 1 and 2.
•
Wire the output run request to connector X58,
terminals 1 and 2.
•
Wire the input run permission to connector X55,
terminals 1 and 2 per the system application.
Disable run permissive
•
Run permissive is enabled by factory default
when ordered.
•
To disable the run permissive function, jumper
between terminals 1 and 2 on connector X55.

5.1.5 EMB Overload

General information
The 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
Option Panel Operating Instructions
provided. In drive mode, the drive provides current sensing
and trip protection. Fuses provide quick action for high
over current conditions.
Before enabling overload
MOTOR DAMAGE!
REPEATED ATTEMPTS TO RESET OVERLOAD CAN CAUSE
MOTOR DAMAGE. CORRECT OVERLOAD CONDITION AND
LET OVERLOAD AND MOTOR RETURN TO NORMAL
OPERATING TEMPERATURE BEFORE RESETTING. SEE MOTOR
MANUFACTURER'S RECOMMENDATIONS FOR TIME
BETWEEN START ATTEMPTS. FAILURE TO CORRECT
OVERLOAD CONDITION AND LET MOTOR RETURN TO
NORMAL OPERATING TEMPERATURE COULD CAUSE
MOTOR DAMAGE.
Operation
Overloads are 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 delay of 20 s or
less at 600% current and normal operating temperature.
This allows for high motor inrush current for 20 s while the
motor is ramping up to synchronous speed. The trip time,
however, is based on the percentage of overload. The
higher the overload, the shorter the trip time. It is
important that the overload class not exceed the motor
class rating or motor damage could occur. For dual motor
operation, an overload is provided for each motor. For
contact motor select, one overload is provided and
monitors either motor when selected.
Overload function setup
®
MG14I102 - VLT is a registered Danfoss trademark
•
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 range of
the current dial, reconfirm that the motor hp and
voltage are within the option panel (and drive)
rating. If less than the FLA rating, replace the
overload with the correct size. If greater than the
FLA rating, replace the panel with one of a
proper rating.
CAUTION
•
Set the overload current dial to the FLA of the
motor. DO NOT add the service factor of the
motor into the setting. A service factor of 120%
for Class 20 is designed into the overload.
•
Pressing the test pushbutton verifies the
operation of the overload. The overload should
trip when pressed. Use the reset pushbutton to
reset the overload after test.
•
Reset is used to reset the overload after it trips. If
the overload is still hot, wait until the motor
reaches normal operating temperature before
resetting. The overload offers a manual (hand) or
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