Siemens 1FT7 Configuration Manual

Technical data and characteristic curves
4.1 Operating range and characteristics
1FT7 Synchronous Motors
Configuration Manual, (PFT7S) 01/2009, 6SN1197-0AD13-0BP2
77
P1 Intersection between voltage limiting characteristic and x axis: Read off or calculate
the speed
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8
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P2 The point where the voltage limiting characteristic intersects with the x axis is shifted
from n
1
to n
2.
.
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P3 Read-off M
limit
on the voltage limiting characteristic curve specified for V
mot
.
P4 Calculate M
limit, new
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The offset voltage limiting characteristic curve is obtained with points P2 and P4.
Example of offset of voltage limiting characteristic curve without field weakening
Motor 1FT7042-5AF71; n
N
= 3000 RPM; k
E
= 87 V/1000 RPM
U
mot new
= 290 V; calculated with U
mot
= 380 V (diagram [a])
U
iN
= k
E
∙ n
N
/1000; U
iN
= 87 ∙ 3000/1000 = 261 V
Condition U
mot, new
> U
iN
is fulfilled.
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Enter and connect points P2 and P4. This line is the new voltage limiting characteristic for
U
mot new
= 290 V.

Siemens 1FT7 Specifications

General

Brand	Siemens
Model	1FT7
Category	Engine
Language	English