Rockwell Automation Allen-Bradley Guardmaster 440R-S35011, User Manual, Page: 32 / 50

32 Rockwell Automation Publication 440R-UM014D-EN-P - December 2019
Chapter 7 Application and Wiring Examples
Wye-Delta Connections
Figure 18 shows a typical wye-delta application where the MSR55P safety relay
monitors the speed of a motor that contactors turn on and off. When the
MSR55P safety relay detects that the motor has achieved its standstill settings,
the MSR55P safety relay energizes its outputs. You must perform a risk
assessment to determine the proper settings of V
m
and t
s
.
Figure 18 - Wye-delta Connections
Table 9 - Wye Delta Connections
Application Description
Main Start When the main switch is closed, the wye contactor (K2) energizes and allows a start.
Production Start Press Start to pull in K1. The K1 contacts hold in the start circuit, starts the rotation of the motor and 700-FEY2QU23 timer relay begins timing. After the
time expires, the 700-FEY2QU237 relay drops out the K2 wye contactor and pulls in the K3 delta contactor. The motor is now running at full speed and
torque.
Production Stop Press the Stop button. The K1 contactor drops out, the 700-FEY2QU237 opens its outputs, and the motor coasts to a stop. When the motor spins down
to a speed below the V
m
setting of 70 mV, the MSR55P safety relay begins its timing sequence. After 3 seconds, the MSR55P safety relay energizes its
outputs.
Safety Stop When the MSR55P safety relay energizes its outputs, K4 and K5 are used to execute the necessary safety stops.
Safety Rating The speed monitoring function that is performed by the MSR55P safety relay meets the requirement of Category 4, PLe per ISO13849-1 and SIL CL 3 per
IEC 60261. The rating of the safety functions initiated by K4 and K5 depends on additional circuitry that is not shown.
MSR55P
440R-S35011
K3
18
17
A1
A2 28
K2
K4
K5
K2
K3
Start
Stop
700-
FEY2QU23
Main switch
240V AC
L2
L1
L3
N
K1
K1 K2
M
3~
U1
W2
V1
U2
W1
V2
K1
K1
K1
K2 K3
K4 K5
NOTES
1. K2 and K3 must be mechanically interlocked.
2. With“3-phase”connection of MSR55P the wye contactor, K2, must be closed after the motor is switched off to detect standstill.
If this is not the case the failure signal “broken wire” blocks the output contacts in off posisition.
MSR55P
440R-S35011
A2
X1
X2
L3 L2 L1
X3
34 44
A1 A3 33 23 11
24 12 ON ERR A4 54
43 53
.2 .3 .5.7
1
1.5
6
3
4
2
ts
2 3 4 5
7
10
20
30
40
15
Vm
x10mV
IMPORTANT • K2 and K3 must be mechanically interlocked.
• With3-phase connection of MSR55P safety relay, the wye contactor (K2)
must be closed after the motor is switched off to detect standstill. If not
the failure signal “broken wire” blocks the output contacts in the off
position.