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I.L. 17562
PR 0.3 Effective 8/99
NOTE
This UTC setting is where the user considers the service factor rating of the motor. Never adjust
the
FLA
setting P1L1 according to the service factor (see subsection 9.1.3.3).
For normal use, set UTC to
service factor
times 100 %. The available range is 85% to 150%.
The service factor is found on the motor nameplate or in manufacturer’s data.
Note that the relay will not trip at the moment the current goes above UTC during motor running.
Instead, it models the gradual stator heating for currents above UTC, and will trip only after some
time has passed. The trip time depends on a variety of setpoint and operating factors, including
motor nameplate data contained in other setting values.
Use a conservative, or lower, value of UTC than that dictated by the service factor if motor
ambient temperatures may rise above 40ºC and the optional URTD Module is not used (see
Subsection 9.1.3.6). Also, consider lowering the UTC if the motor is suitably rated, yet additional
safety is critical for the application.
CAUTION
If UTC is set above 100 percent times the service factor, motor damage could result.
5.1.5 Setpoint P1L5, Phase Current Transformer Ratio (PCT) —
Specifies the numerator of
the turns ratio of the main phase current transformers. Obtain from the Ct nameplate or from the
installation drawings, watching for the use of ratio taps on Cts which have tapped windings.
Explanation of Ct Ratio Presentation
The MP-3000 motor relay is available in multiple styles designed for use with current
transformers (Cts) having a nominal or rated secondary current of either 5 amperes or 1 ampere.
Check the relay labeling or the catalog number, and the Ct secondary rating, to confirm a match.
All displayed information is the same for either of the two types of MP-3000 relays. When Ct
ratios are to be set, the value entered is the
numerator
of the main Ct ratio. The denominator is
assumed to be either 5 or 1, depending on the rating of the cts and relay in use.
For example, a set of three 400:5 phase Cts might be used with an MP-3000 specified for 5 A
Cts. The phase Ct ratio is then set to 400. Alternatively, a set of three 400:1 Cts could be used
with an MP-3000 rated for 1 A cts. Use a setting of 400 in this case as well.
Ct Ratio Selection
Check the following criteria to insure a suitable current transformer ratio:
For a 5 ampere Ct set:
For optimum metering accuracy at low loads, the Ct should deliver between 3.5 and 4 amperes
at 100 percent FLA. Attempt to achieve 3.75 A.
For reliable motor protection, the Ct must deliver between 2.5 and 4 amperes at
100 percent FLA.
For example, if the motor has an FLA value of 300A, a 400:5 Ct will supply:
Содержание 66D2032G01
Страница 18: ...Page 18 I L 17562 PR 0 3 Effective 8 99 Figure 4 1 MP 3000 Pushbuttons...
Страница 19: ...I L 17562 Page 19 PR 0 3 Effective 8 99 Figure 4 2 MP 3000 LED Indicators...
Страница 72: ...Page 72 I L 17562 PR 0 3 Effective 8 99 Figure 6 1 Panel Cutout Dimensions...
Страница 73: ...I L 17562 Page 73 PR 0 3 Effective 8 99 Figure 6 2 Faceplate Dimensions...
Страница 74: ...Page 74 I L 17562 PR 0 3 Effective 8 99 Figure 6 3 MP 3000 Case Depth Dimensions...
Страница 75: ...I L 17562 Page 75 PR 0 3 Effective 8 99 Figure 6 4 Universal RTD Module Mounting Dimensions...
Страница 76: ...Page 76 I L 17562 PR 0 3 Effective 8 99 Figure 6 5 Rear Panel Terminals...
Страница 77: ...I L 17562 Page 77 PR 0 3 Effective 8 99 Figure 6 6 Typical Ct Circuits and Motor Control Wiring...
Страница 78: ...Page 78 I L 17562 PR 0 3 Effective 8 99 Figure 6 7 Typical ac Supply and URTD Wiring...
Страница 79: ...I L 17562 Page 79 PR 0 3 Effective 8 99 Figure 6 8 Alternatives for Discrete Input Wiring...
Страница 80: ...Page 80 I L 17562 PR 0 3 Effective 8 99 Figure 6 9 RTD Wiring to URTD Module...
Страница 88: ...Page 88 I L 17562 PR 0 3 Effective 8 99 Figure 8 1 System Overview Figure 8 2 Torques from Sequence Currents...
Страница 100: ...Page 100 I L 17562 PR 0 3 Effective 8 99 Figure 9 1 Rotor Temperature Tracking...
Страница 101: ...I L 17562 Page 101 PR 0 3 Effective 8 99 Figure 9 2 Motor Protection Curve...
Страница 102: ...Page 102 I L 17562 PR 0 3 Effective 8 99 Figure 9 3 Underload Jam Protection Curve...
Страница 103: ...I L 17562 Page 103 PR 0 3 Effective 8 99 Figure 9 4 Motor Protection Curve Example without RTDs...
Страница 104: ...Page 104 I L 17562 PR 0 3 Effective 8 99 Figure 9 5 Motor Protection Curve Example with RTDs...
Страница 105: ...I L 17562 Page 105 PR 0 3 Effective 8 99 Figure 9 6 Motor Start and Run Cycles...
Страница 109: ...I L 17562 Page 109 PR 0 3 Effective 8 99 P5L8 40 Incomplete Sequence time 1 60s OFF 1 240s...