PLS Drip-proof 3-phase induction motors - Etum Elektronik
PLS Drip-proof 3-phase induction motors - Etum Elektronik
PLS Drip-proof 3-phase induction motors - Etum Elektronik
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D1.2 - EFFECTS ON MOTOR<br />
PERFORMANCE<br />
D1.2.1 - Voltage range<br />
The characteristics of <strong>motors</strong> will of course<br />
vary with a corresponding variation in<br />
voltage of ±10% around the rated value.<br />
An approximation of these variations is<br />
given in the table opposite (precise values<br />
for each motor can be supplied on request).<br />
D1.2.2 - Simultaneous variation<br />
of voltage and frequency<br />
Within the tolerances defined in IEC guide<br />
106, machine input and performance are<br />
unaffected if the variations are of the same<br />
polarity and the voltage/frequency ratio U/f<br />
remains constant.<br />
If this is not the case, variations in<br />
performance are significant and require the<br />
machine specification to be changed.<br />
D1.2.3 - Phase voltage imbalance<br />
The <strong>phase</strong> imbalance for voltage is<br />
calculated as follows:<br />
% Voltage<br />
imbalance = 100 x<br />
The effect on motor performance is<br />
summarized in the table opposite.<br />
If this imbalance is known before the motor<br />
is purchased, it is advisable, in order to<br />
establish the type of motor required, to<br />
apply the derating specified in standard IEC<br />
60892, illustrated on the graph opposite.<br />
D1.2.4 - Phase current imbalance<br />
Voltage imbalances induce current<br />
imbalances. Natural lack of symmetry due<br />
to manufacture also induces current<br />
imbalances.<br />
<strong>PLS</strong><br />
<strong>Drip</strong>-<strong>proof</strong> 3-<strong>phase</strong> <strong>induction</strong> <strong>motors</strong><br />
Operation<br />
maximum difference in voltage<br />
compared to average voltage<br />
value<br />
average voltage value<br />
D1 - Supply voltage<br />
Torque curve<br />
Slip<br />
Rated current<br />
Rated efficiency<br />
Rated power factor (Cos ϕ)<br />
Starting current<br />
Nominal temperature rise<br />
P (Watt) no-load<br />
Q (reactive V A) no-load<br />
* According to standard IEC 60034-1, the additional temperature rise must not exceed 10 K within ±5% of UN.<br />
Variation in main motor parameters (approx.) within the limits defined in IEC Guide 106.<br />
M = minimum and maximum values of starting torque.<br />
Voltage variation as a %<br />
UN-10%<br />
UN-5%<br />
UN<br />
UN+5%<br />
UN+10%<br />
0.81 0.90 1 1.10 1.21<br />
1.23 1.11 1 0.91 0.83<br />
1.10 1.05 1 0.98 0.98<br />
0.97 0.98 1 1.00 0.98<br />
1.03 1.02 1 0.97 0.94<br />
0.90 0.95 1 1.05 1.10<br />
1.18 1.05* 1 1* 1.10<br />
0.85 0.92 1 1.12 1.25<br />
0.81 0.9 1 1.1 1.21<br />
U /f Pu M N Cos ϕ<br />
Constant<br />
Variable<br />
Percentage<br />
imbalance<br />
Stator current<br />
Increase<br />
in losses<br />
Temperature rise<br />
Pu M<br />
f'<br />
- N<br />
f<br />
f'<br />
-<br />
f<br />
Pu f'<br />
-<br />
f<br />
u' ⎛<br />
⎝<br />
--- ⎞<br />
u⎠<br />
2<br />
0 2 3.5 5<br />
u' u<br />
M ⁄ ( )<br />
--------------f⁄<br />
f'<br />
2<br />
100 101 104 107.5<br />
0 4 12.5 25<br />
1 1.05 1.14 1.28<br />
Derating facotr<br />
1.0<br />
0.9<br />
0.8<br />
N f'<br />
-<br />
f<br />
cos ϕ<br />
unchanged<br />
Depends on level<br />
of saturation<br />
of machine<br />
Efficiency<br />
Efficiency<br />
unchanged<br />
0.7<br />
0 1 2 3 4 5<br />
Percentage voltage imbalance<br />
33
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