GE M60 UR Series

5-164 M60 Motor Protection System GE Multilin
5.6 GROUPED ELEMENTS 5 SETTINGS
5
Figure 5–71: AMP UNBALANCE SCHEME LOGIC
e) MECHANICAL JAM
PATH: SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  MOTOR  MECHANICAL JAM
A motor load can become constrained (mechanical jam) during starting or running. The starting current magnitude alone
cannot provide a definitive indication of a mechanical jam; however, the running current magnitude can. The Mechanical
Jam element is specifically designed to operate for running load jams. Starting load jams are detected by monitoring accel-
eration time and speed. The thermal element will also operate during mechanical jams but after a delay when the thermal
capacity reaches 100%. Not only is this ineffective due to the delay but it also implies the maximum waiting time for cooling
before a re-start, which could be restrictive.
This element is armed as long as the motor status is not “Starting”; this includes “Running”, “Overload”, and “Offline”. As
soon as any phase current exceeds the user-selectable threshold, the element picks up and operates after the pro-
grammed time delay. The element uses currents configured under
SYSTEM SETUP  MOTOR  MOTOR LINE SOURCE and
motor status asserted by the thermal model element. Both the signal source and thermal protection must be configured
properly in order for the mechanical jam protection to operate.
 MECHANICAL JAM

MECHANICAL JAM
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
MECH JAM OVERCURRENT
PICKUP: 2.00 x FLA
Range: 1.00 to 10.00 x FLA in steps of 0.01
MESSAGE
MECH JAM PICKUP
DELAY: 0.10 s
Range: 0.10 to 600.00 s in steps of 0.01
MESSAGE
MECH JAM RESET
DELAY: 0.00 s
Range: 0.00 to 600.00 s in steps of 0.01
MESSAGE
MECH JAM BLOCK:
Off
Range: FlexLogic operand
MESSAGE
MECH JAM TARGET:
Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
MECH JAM EVENTS:
Disabled
Range: Disabled, Enabled
AMP UNBAL 1
FUNCTION:
AMP UNBAL 1
BLK:
AMP UNBAL 1
PICKUP RESET:
AMP UNBALANCE 1 PKP
AMP UNBALANCE 1 DPO
AMP UNBALANCE 1 OP
AMP UNBAL 1
PICKUP DELAY:
AMP UNBAL 1
PICKUP:
SYSTEM SETUP/MOTOR/
MOTOR LINE SOURCE:
Off = 0
RUNI_1
IA
IA < 0.02 FLA*
IA+IB+IC
3
If Iavg FLA*, K=1
If Iavg < FLA*, K=
>
=
>
=
>
=
= Iavg
IB
IB < 0.02 FLA*
IC
IC < 0.02 FLA*
UNBAL > 40 %
Iavg 0.25 FLA*
UNBAL PKP 1
I_2
Enabled = 1
SETTING
SETTING
FLEXLOGIC OPERANDS
FLEXLOGIC OPERAND
SETTING
SETTINGSETTING
833002A5.CDR
NOTE:
- FLA is programmed in
SYSTEM SETUP / MOTOR / FULL LOAD AMPS
*
AND
AND
AND
AND
OR
OR
OR
AND
AND
Iavg
FLA*
Kx x100%
I_2
I_1
2s
0
t
PKP
RST
t
AMP UNBALANCE
ACTUAL VALUES