Parameterization
SRW 01 | 5-51
5
The closer to class 40, the closer one gets to the motor maximum limit. Therefore, more starts per hour and
smaller intervals between stopping and restarting the motor will be possible.
5.7.15.1 Reduction of the Time from Cold to Warm Starting
In order to determine the warm actuation times of the tripping classes when the motor is operating with full load
and current equal or below 100 % of In, the
multiplying factor must be used, according
to the current percentage that the motor is taking continuously.
E.g.:
A motor is being operated with 80 % of In and it is switched off.
It is started again immediately.
The starting regimen is 3 x In @ 25 s.
The selected tripping class is Class 10 with 33.7 s @ 3 x In.
The multiplying factor of the
for 80 % In is 0.48.
The final actuation time will be: 0.48 x 33.7 s = 16.2 s, i.e., the time has been reduced from 33.7s for a cold
starting to 16.2 s for a warm starting, therefore, another start will not be possible before the motor thermal image
diminishes, i.e., the motor cools down.
5.7.16 Phase Sequence
The phase sequence protection aims at protecting loads that can only rotate in a single direction. When
enabled by means of parameter P648, it only allows the phase sequence selected in parameter P408 – Motor
Phase Sequence, direct phase sequence (1-2-3) or reverse (3-2-1).
The phase sequence is detected from the reading of the power supply voltage signals. If the sequence is different
from that adjusted in P408, a Trip signal is generated preventing the activation of the motor. There is no timing
adjustment for this protection. The cause of the fault is generally related to the improper connection of the motor
power supply cables.
P648 – Phase Sequence
Adjustable
Range:
0 = Disabled
1 = Enabled
Factory
Setting:
0
Proprieties:
Sys, rw
Description:
It enables and disables the phase sequence protection.
NOTE!
The phase sequence protection only works for three-phase motors. It is only available when the
Current/ Voltage Measurement Unit (UMCT) is used and voltage is present in the three phases of the
motor.
5.7.17 Voltage Unbalance
The voltage unbalance protection monitors the three phases of the motor, calculating the voltage unbalance as
per equation 3. If the unbalance calculated is greater than that adjusted in parameter P649 for the timer adjusted
in parameter P650, the motor can be shut down or just an alarm can be activated, according to parameter P651.
The unbalance protection follows the recommendations of standard NEMA MG1. NEMA MG1 does not recommend
the operation of a motor above 1 % of voltage unbalance without reducing the motor capacity (derating). If the
voltage unbalance in the motor terminals exceeds 3 %, the motor capacity must be derated to 90 %, and to 75 % if
the unbalance is of 5 %. The standard also does not recommend the operation of a motor with a voltage unbalance
level above 5 % under any circumstances. A voltage unbalance level of 5 % corresponds to 30 to 50 % of unbalance
in the current. Consequently, the greater the voltage unbalance, the greater the increase in the motor current and
temperature. Contact the motor manufacturer for the voltage unbalance tolerances.
Summary of Contents for SRW 01
Page 2: ......
Page 8: ...Contents...
Page 108: ...Parameterization 5 62 SRW 01 5...
Page 128: ...Monitoring 6 20 SRW 01 6...
