Emerson Powerdrive F300 Reference Manual page 61

Motor Protection Accumulator Power-
up Value (04.036)
Power Down
Zero
Real Time
The Motor Protection Accumulator (04.019) is reset under the following conditions:
1. Motor Thermal Time Constant 1 (04.015) is set to 0.0. Note that this is not possible in the standard product as the minimum parameter value is
1.0.
2. Select Motor 2 Parameters (11.045) is modified.
3. Rated Current (05.007) is modified when Select Motor 2 Parameters (11.045) = 0, or M2 Rated Current (21.007) is modified when
Select Motor 2 Parameters (11.045) = 1.
4. Thermal Protection Mode (04.016) is modified.
Motor Protection Accumulator Warning
If Percentage Losses > 100% then eventually the Motor Protection Accumulator (04.019) will reach 100% causing the drive to trip or the current limits to
be reduced. If this is the case and Motor Protection Accumulator (04.019) > 75.0% then [Motor Overload] alarm indication is given
and Motor Overload Alarm (10.017) is set to one.
Parameter 04.016 Thermal Protection Mode
Short description Set to the require thermal protection mode
Mode Open‑Loop
Minimum 0
Default 0
Type 8 Bit User Save
Display Format Standard
Coding RW, TE
Value Text
0 Motor Trip
1 Motor Limit
2 Drive Limit
3 Both Limit
4 Disabled
Thermal Protection Mode (04.016) defines the action taken by the drive when Motor Protection Accumulator (04.019) reaches 100%
and/or Percentage Of Drive Thermal Trip Level (07.036) exceeds 90%. The actions for each mode are given in the table below.
Thermal Protection Mode (04.016)
Motor Trip (0)
Motor Current Limit (1)
Drive Current Limit (2)
Motor and Drive Current Limit (3)
Disabled (4)
The current limit is derived from the current limit parameters (i.e. Motoring Current Limit (04.005), etc.) depending on the set-up and conditions. The
current limit can be further limited by current limit on motor overload and/or drive temperature monitoring as shown below to give the Final Current Limit
(04.018).
Powerdrive F300 Parameter Reference Guide
Issue: 01.15.00
Motor Protection Accumulator (04.019) at power-up
The value is saved at power-down and is used as the initial value at power-up.
The value is set to zero
If a real-time clock is present and if Date/Time Selector (06.019) is set up to select the real-time clock then
the value saved at power-down is modified to include the effect of the motor thermal protection time
constants over the time between power-down and power-up. This modified value is then used as the initial
value at power-up.
If no real time clock is present then and this option is selected then the value saved at power-down is used
as the initial value.
Maximum
Units
Update Rate
Decimal Places
Actions
Motor Too Hot trip is initiated when Motor Protection Accumulator (04.019) reaches 100%.
No current limiting.
Motor Protection Accumulator (04.019) is limited to 100.0%.
Motor Too Hot trip is disabled.
Current limiting on motor overload as described below.
Motor Protection Accumulator (04.019) is limited to 100.0%.
Motor Too Hot trip is initiated when Motor Protection Accumulator (04.019) reaches 100%.
Current limiting on drive thermal monitoring as described below.
Motor Protection Accumulator (04.019) is limited to 100.0%.
Motor Too Hot trip is disabled.
Current limiting on motor overload and drive thermal monitoring as described below.
Motor Protection Accumulator (04.019) is limited to 100.0%.
Motor Too Hot trip is disabled and Motor Overload alarm is disabled.
No current limiting.
Motor Protection Accumulator (04.019) is limited to 200.0%.
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Background read
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