Delta Three Phase 1342457 06-03-05 Service Manual download pdf (Page 147)

June 2005

CAT.02.02.S.K.CD For more information visit: www.EatonElectrical.ca

145

XT IEC Power Control

Manual Motor Protectors

Technical Data and Speciﬁcations

Time/Current Curve

Characteristics

The time/current characteristic, the current limiting charac-

teristics and the I

t characteristics were determined in accor-

dance with DIN VDE 0660 and IEC 60 947.

The tripping characteristic of the inverse-time delayed over-

load releases (thermal overload releases or “a” releases) for

DC and AC with a frequency of 0 to 400 Hz also apply to the

time/current characteristic.

The characteristics apply to the cold state. At operating

temperature, the tripping times of the thermal releases are

reduced to approximately 25%.

Under normal operating conditions, all three poles of the

device must be loaded. The three main conducting paths

must be connected in series in order to protect single-phase

or DC loads.

With 3-pole loading, the maximum deviation in the tripping

time for 3 times the setting current and upwards is ±20% and

thus in accordance with DIN VDE 0165.

The tripping characteristics for the instantaneous, electro-

magnetic overcurrent releases (short-circuit releases or “n”

releases) are based on the rated current I

, which is also the

maximum value of the setting range for circuit-breakers with

adjustable overload releases. If the current is set to a lower

value, the tripping current of the “n” release is increased by

a corresponding factor.

The characteristics of the electromagnetic overcurrent

releases apply to frequencies of 50/60 Hz. Appropriate

correction factors must be used for lower frequencies up to

16-2/3 Hz, for higher frequencies up to 400 Hz and for DC.

Time/current characteristics, current limiting characteristics

and I

t characteristics are available on request.

Figure 76. MMP Tripping Characteristics — XTPB, XTPR Frame B and

XTPT (not for XTPM)

Figure 77. MMP Tripping Characteristics — XTPR Frame D

200

1.5

XTPB, XTPR Frame B

XTPT

Seconds

Milli-seconds

Minutes

x Rated Operational Current

XTPR Frame D

200

1.5

Seconds

Milli-seconds

Minutes

x Rated Operational Current

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