Rockwell Automation Allen-Bradley Guardmaster 440R-S35011, Руководство пользователя

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Rockwell Automation Publication 440R-UM014D-EN-P - December 2019 7
Chapter
1
Overview
Safety Relay Features Figure 1 - Overview of Key Features
MSR55P back electro-motive-force (EMF) safety relays monitor the voltage
that motors generate after their drive voltage is removed and the motor coasts
or brakes to a stop. MSR55P safety relays monitor either single- or three-phase
motors. MSR55P safety relays operate with pulse width modulated (PWM)
drives, smart motor controllers, and electromechanical contactors.
MSR55P safety relays are connected to the motor terminals and measure the
induced back EMF as the motor spins to a stop. MSR55P safety relays create a
two-channel system by measuring the voltage from L2 to L1 and the voltage
from L3 to L1. If the back EMF voltage drops to a certain threshold
simultaneously in both channels for a certain duration, standstill is considered
achieved, and the outputs are energized.
If the voltage measured on terminals L1/L2/L3 of the MSR55P safety relay
rises over the adjusted value plus hysteresis in at least one channel (the motor is
switched on or the shaft turns mechanically), the forcibly guided output
contacts are switched off immediately (contacts 23/24, 33/34 and 43/44 open
while contact 11/12 closes). The monitoring relay de-energizes (53/54
opened), the semiconductor output ON goes off and the OUT indicator turns
yellow (= V
m
over adjusted value).
To accommodate many types of motors, you can make two adjustments in
accordance with the machine risk assessment:
• The threshold of the back EMF voltage.
• A time delay to add additional assurance that the motor has stopped.
Removable terminal blocks
Standstill voltage setting
Standstill time delay setting
Three indicators for status
and diagnostics