Emerson Mentor MP Advanced User's Manual page 144

Parameter
Menu 11
structure
External
%
resistor
temperature
Pr 11.65
100
0
Pr 11.62
Assuming that the full power braking time is much shorter than the full power braking period (which is normally the case) the values for Pr 11.60 and
Pr 11.61 can be calculated as follows:
(
SuppressorVolts
-------------------------------------------------------------- -
Power =
Pr11.62
Full power discharge time (Pr 11.60)
Energy
T --------------------- -
=
on
Power
Where Energy is the total energy that can be absorbed by the external resistor when its initial temperature is ambient temperature.
⇒
(
Disch arg eTime Pr11.60
If the cycle shown in the diagram above is followed repeatedly, where the external resistor is heated to its maximum temperature and then cools to
ambient:
The average power in the resistor
P = Disch arg
average
where Tp is the full power braking period (Pr 11.61)
⇒
------------------------------------ -
Disch arg ePower =
T
⇒ Energy
-------------------------------- -
AveragePower =
T
p
⇒
Disch arg ePower Pr11.61 T
The temperature of the external resistor is monitored by the temperature accumulators (Pr 11.63). When parameter Pr 11.62 reaches 100% the drive
will trip 'O.ht3'.
11.64 External discharge resistance
Bit SP
Coding
Range 0 to 9999Ω
Default 0
Update rate Background read
This parameter defines the external resistance fitted to the drive by the user. This parameter is used in calculating the power dissipated and modelling
the temperature of the resistor.
144
Keypad and
Parameter x.00
display
Pr 11.61
) 2
)T ×
= Energy
-------------------------------------------------------------- -
on
(
SuppressorVolts
T
on
× ---------- -
ePower = Disch arg
T
p
Energy
Pr11.60
on
Pr11.61
Energy
----------------------------------------------
=
p
AveragePower
FI DE Txt VM DP ND
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Parameter description
format
Pr11.62
) 2
Pr11.60
× --------------------- -
ePower
Pr11.61
RA NC NV PT US RW BU
1
Advanced parameter Serial comms
descriptions protocol
t
PS
1 1
Mentor MP Advanced User Guide
Performance
Issue Number: 1