6 Protection Functions
P50 Agile P253
6-6
P253/EN M/C
the current fails to fall below the current threshold before the stall time delay has elapsed, a trip is
initiated.
2.2
Number of Starts Limitation (66)
Repeated starting or intermittent operation of a motor may generate high temperatures within the
motor, unless sufficient time is allowed for cooling between two or more starts. The P253 motor
protection relay incorporates a number of starts limitation facilities, fully programmable and applicable
to both hot and cold start conditions.
2.2.1
Starts Inhibition
Motors can be started a limited number of times in a defined period without exceeding the permitted
winding temperatures. The settings in the
Limit NB STARTS
protection menu monitor these starts.
Two types of starts are supervised:
•
Hot Starts are defined by an initial thermal state greater than 50%
•
Cold Starts are defined by an initial thermal state lower than 50%
The maximum allowable number of starts per period is an auto-reset inhibit function. This function
monitors the number of motor starts in the set period. At the end of the period the number of starts is
decremented.
Starts are detected using the 52a status from the breaker. Once the number of starts equals the user-
defined setting, the start inhibit is enabled for the set period (
Inhibit Strt Time
).
Start inhibition function is explained with the help of following examples:
Start inhibition example 1:
The maximum number of starts within the
Supervising Time
has been reached so the
Inhib. Strt
Time
is initiated. The remaining time Supervising Time – tn is greater than the
Inhib. Strt Time
, so the
start inhibition remains for a duration equal to
Supervising Time
– tn. Therefore, with the default
settings and a tn of 8 mins for example, the inhibition time before a new start is 52 mins.
Summary of Contents for P50 Agile P253
Page 3: ...P50 Agile P253 1 Introduction P253 EN M C 1 1 INTRODUCTION CHAPTER 1 ...
Page 4: ...1 Introduction P50 Agile P253 1 2 P253 EN M C ...
Page 11: ...SAFETY INFORMATION CHAPTER 2 ...
Page 12: ...Safety Information Pxxx 2 ...
Page 23: ...P50 Agile P253 3 Hardware Design P253 EN M C 3 1 HARDWARE DESIGN CHAPTER 3 ...
Page 24: ...3 Hardware Design P50 Agile P253253 3 2 P253 EN M C ...
Page 28: ...3 Hardware Design P50 Agile P253253 3 6 P253 EN M C E00276 Figure 2 Hardware design overview ...
Page 32: ...3 Hardware Design P50 Agile P253253 3 10 P253 EN M C ...
Page 33: ...P50 Agile P253 4 Front Panel P253 EN M C 4 1 FRONT PANEL CHAPTER 4 ...
Page 34: ...4 Front Panel P50 Agile P253 4 2 P253 EN M C ...
Page 39: ...P50 Agile P253 4 Front Panel P253 EN M C 4 7 Figure 2 USB port ...
Page 40: ...4 Front Panel P50 Agile P253 4 8 P253 EN M C ...
Page 41: ...P50 Agile P253 5 Configuration P253 EN M C 5 1 CONFIGURATION CHAPTER 5 ...
Page 42: ...5 Configuration P50 Agile P253 5 2 P253 EN M C ...
Page 154: ...5 Configuration P50 Agile P253 5 114 P253 EN M C ...
Page 155: ...P50 Agile P253 6 Protection Functions P253 EN M C 6 1 PROTECTION FUNCTIONS CHAPTER 6 ...
Page 156: ...6 Protection Functions P50 Agile P253 6 2 P253 EN M C ...
Page 182: ...7 Protection Parameter Settings P50 Agile P253 7 2 P253 EN M C ...
Page 203: ...P50 Agile P253 8 Monitoring Control P253 EN M C 8 1 MONITORING CONTROL CHAPTER 8 ...
Page 204: ...8 Monitoring Control P50 Agile P253 8 2 P253 EN M C ...
Page 222: ...8 Monitoring Control P50 Agile P253 8 20 P253 EN M C ...
Page 223: ...P50 Agile P253 9 SCADA Communications P253 EN M C 9 1 SCADA COMMUNICATIONS CHAPTER 9 ...
Page 224: ...9 SCADA Communications P50 Agile P253 9 2 P253 EN M C ...
Page 249: ...P50 Agile P253 10 Installation P253 EN M C 10 1 INSTALLATION CHAPTER 10 ...
Page 250: ...10 Installation P50 Agile P253 10 2 P253 EN M C ...
Page 260: ...11 Commissioning Instructions P50 Agile P253 11 2 P253 EN M C ...
Page 270: ...11 Commissioning Instructions P50 Agile P253 11 12 P253 EN M C ...
Page 272: ...12 Maintenance and Troubleshooting P50 Agile P253 12 2 P253 EN M C ...
Page 282: ...13 Technical Specifications P50 Agile P253 13 2 P253 EN M C ...
Page 292: ...13 Technical Specifications P50 Agile P253 13 12 P253 EN M C ...
Page 293: ...P50 Agile P253 14 Wiring Diagrams P253 EN M C 14 1 WIRING DIAGRAMS CHAPTER 14 ...
Page 294: ...14 Wiring Diagrams P50 Agile P253 14 2 P253 EN M C ...
Page 297: ......