Discontinuous Current Controller Ki Gain; Extra Safe Bridge Change; Reduced Hysteresis For Bridge Change Over - Emerson Mentor MP Advanced User's Manual

Parameter
Menu 4
structure
4.34

Discontinuous current controller Ki gain

Bit SP
Coding
Range 0 to 4000
Default 200
Second motor
Pr 21.12
parameter
Update rate Background read
This parameter is set to correct any errors in the prediction of firing angle in the discontinuous current region.
Pr 4.34 = 1131 x R x Imax / V rms
Where :
L is the load inductance in Henries
R is the load resistance in ohms
f is the supply frequency in Hertz
Imax is the peak load current (including any overload) in amps
V rms is the line-to-line supply voltage in volts.
4.35

Extra safe bridge change

Bit SP
Coding
1
Default 0
Update rate Background read
When enabled an additional safety margin of 1 supply cycle is added to the bridge changeover logic. This may be required for highly inductive loads,
such as a motor field.
4.36

Reduced hysteresis for bridge change over

Bit SP
Coding
1
Default 0
Update rate Background read
There is hysteresis on bridge change over to prevent oscillation between the two bridges under lightly loaded conditions. In applications which require
fine control of the current the bridge change over hysteresis can be reduced from 1.6 % to 0.2 % of the drive maximum current by setting this
parameter.
68
Keypad and
FI DE Txt VM DP ND
FI DE Txt VM DP ND
FI DE Txt VM DP ND
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Advanced parameter
format
Parameter description
RA NC NV PT US RW BU
1 1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
Serial comms
protocol
descriptions
PS
1
PS
PS
Mentor MP Advanced User Guide
Performance
Issue Number: 4