Fault Setup Parameters - Allen-Bradley 1395 Troubleshooting Manual

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2-4 Malfunctions with Indications

Fault Setup Parameters

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Certain Faults have setup parameters associated with them. They allow the
user to set thresholds and time delays according to the particular
application. A description of faults with setup parameters follows:
No. Name Description
VP-10 Feedback This Soft fault occurs when the
Loss measured velocity feedback from
the selected feedback device is less
than parameter 732 "Tach Loss Vel"
and the CEMF of the motor is
greater than parameter 731 "Tach
Loss CEMF".
Velocity Fdbk (106) < Tach Loss Vel
(732), AND calculated CEMF from
Arm Voltage Fdbk (105) > Tach Loss
CEMF (731), THEN Fault on
Feedback Loss.
VP-12 Absolute This Soft fault occurs when motor
Overspeed velocity exceeds the maximum
forward/reverse speed limits by the
absolute overspeed level.
VP-13 Motor Field This Soft fault occurs when the field
Loss current feedback is less than 50% of
field current reference for the time
delay specified.
ATTENTION: Uncontrolled motor rotation can cause injury or equipment damage if
field loss detection is disabled. Field loss protection can only be disabled if using an
!
external field supply. Set bit 6 to disable field loss detection.
VP-14 SCR This fault occurs when the SCR heat
Overtemp sink (HST) thermoswitch and/or
vane switch (MKVA) opens after the
specified time delay.
VP-15 External This selectable fault occurs when
Overtemp the external overtemp discrete input
(TB3-1& 2) is low for the time delay
specified.
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Associated Parameter(s)
Parameter 731 "Tach Loss CEMF". This
parameter indicates the lower limit of CEMF of
the motor voltage allowed for determination of
feedback loss. Programmable range is 0-33%.
Parameter 732 "Tach Loss VEL" This parameter
indicates the upper limit of velocity feedback
measured by the selected feedback device
allowed for determination of feedback loss.
Programmable range is 0.244, ±10%.
Parameter 731 "Tach Loss CEMF" must always
be programmed to a value greater than
parameter 732 "Tach Loss VEL" or nuisance trips
will occur.
Parameter 724 "ABS Overspeed" This
parameter indicates the incremental motor
velocity (RPM) above parameter 607 "Rev
Speed Limit" or parameter 608 "Fwd Speed
Limit" that must be detected in parameter 106
"Velocity Fdbk" to cause the above fault.
Programmable range is zero to Base Speed.
See also parameters 607 "Rev Speed Limit" and
608" Fwd Speed Limit".
Parameter 730 "Fld Failure Dly" This parameter
indicates the time the field current feedback
must remain less than 50% of the field current
reference before the above fault is indicated.
Programmable range is 0-5 seconds.
Parameter 627 "Flux Mode Select". Bit 6 can be
used to disable field loss detection. For normal
operation, set it to 0 to detect field loss
conditions.
Parameter 726 "SCR Overtemp Dly". This
parameter indicates the time the thermoswitch
must remain open before the above fault is
indicated. Programmable range: 0-3276.7 secs.
Parameter 725 "Motor Ovtemp Dly". This
parameter indicates the time the discrete input
must remain low before the above fault is
indicated. Programmable range: 0-3276.7 secs.
Verify that the motor thermostat is properly
wired. If the motor is not equipped with a
thermostat, 115 VAC or 24V DC must still be
applied to TB3 terminal 2. See 1395 Installation
Manual (publication 1395-5.40).