External Trip; Drive Reset - Emerson SP1201 Installation Manual

Safety Product
Introduction
Information information
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 10.30 and
Pr 10.31 can be calculated as follows:
Power flowing into the resistor when the braking IGBT is on, P
Where:
Full braking volts is defined in the table and R is the resistance of the braking resistor.
Full power braking time (Pr 10.30), T
Where:
E is the total energy that can be absorbed by the resistor when its initial temperature is ambient temperature.
Therefore full power braking time (Pr 10.30), T
If the cycle shown in the diagram above is repeated, where the resistor is heated to its maximum temperature and then cools to ambient.
The average power in the resistor, P
Where:
Tp is the full power braking period
P = E / T
on on
Therefore P = E / Tp
av
Therefore full power braking period (Pr 10.31), Tp = E / P
The resistance and the braking resistor R, the total energy E and the average power P
calculate Pr 10.30 and Pr 10.31.
If the profile of the power flowing from the motor is know then the instantaneous temperature can be calculated at any point by simulating the braking
resistor with the model shown below.
Power from motor
The temperature of the resistor is monitored by the braking energy accumulator (Pr 10.39). When this parameter reaches 100% the drive will trip if
Pr 10.37 is 0 or 1, or will disable the braking IGBT until the accumulator falls below 95% if Pr 10.37 is 2 or 3. The second option is intended for
applications with parallel connected DC buses where there are several braking resistors, each of which cannot withstand full DC bus voltage
continuously. The braking load will probably not be shared equally between the resistors because of voltage measurement tolerances within the
individual drives. However, once a resistor reaches its maximum temperature its load will be reduced, and be taken up by another resistor.
10.32

External trip

Drive mode Regen
Bit SP
Coding
1
Default Regen
Update rate Background
If this flag is set to one then the drive will trip (Et). If an external trip function is required, a digital input should be programmed to control this bit.
10.33

Drive reset

Drive mode Regen
Bit SP
Coding
1
Default Regen
Update rate Background
A zero to one change in this parameter will cause a drive reset. If a drive reset terminal is required on the drive the required terminal must be
programmed to control this bit.
150
System Mechanical
design installation
= E / P
on on
= E x R / Full braking volts
on
= P x T / Tp
av on on
av
-t/Tp
x (1-e )
100%
PAv
FI DE Txt VM DP ND
0
FI DE Txt VM DP ND
0
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Electrical Getting
Optimisation
installation started
2
= Full braking volts / R
on
2
can normally be obtained for the resistor and used to
av
Braking energy overload
accumulator Pr 10.39
RA NC NV PT US RW BU
1
RA NC NV PT US RW BU
1
Technical Component
Parameters
data
PS
1
PS
1
Unidrive SP Regen Installation Guide
Diagnostics
sizing
Issue Number: 2