testing motors

TP IEC - Routine Tests

Page: 1 of 5 Rev.: 00TEST PROCEDURES 1st Edition

IDENTIFICATION

Test Procedure Number: -

Customer:

Customer reference:

Model: Power:

Voltage: Poles:

Frequency: Mounting:

Classification: -

DEFINITIONS

This procedure applies to induction motors only. It defines and standardizes the tests, which will be performed in order to evaluate the performance of the machine.

The tests shall be conducted regarding to the applicable portions of IEC 61986:2002, IEC60034-8:2002, IEC 61972:2002, IEC 60034-2:1995/1996, IEEE 43:2000 or IEC 60034-1:2004.

If the tolerances are defined on the data sheet, it will take priority at the acceptance criteria.

When a specific test can be performed in more than one method, the manufacturer will select the method available and possible to be performed at the laboratory possibility and availability.

Performed: Clovis Bauer Approved: Glauco Andr Wolff Cisz Date:16/08/2006

WEG EQUIPAMENTOS ELTRICOS S/A - MQUINASAv. Prefeito Waldemar Grubba, 3000 - 89256-900 - Jaragu do Sul - SC - Fone (47) 3372-4000 - Fax (47) 3372-4030 - www.weg.netWEG EQUIPAMENTOS ELTRICOS S/A - MQUINAS - SBC - SPEstrada dos Alvarengas, 5500 - 09850-550 - So Bernardo do Campo - SP - Fone : (11) 2191-6828 - Fax : (11) 2191-6849



TEST LIST

1. Resistance of Windings Applicable

2. No Load Losses and Current Applicable

3. Locked Rotor Current Method 1 Applicable

4. Withstand Voltage Test Applicable

5. Insulation Resistance Applicable

6. Direction of Rotation Applicable

7. Open Circuit Secondary Induced Voltage at Standstill Not Applicable



1. Resistance of Windings

The determination of the ohmic resistance shall be measured among line machine terminals stator windings using a resistance-bridge or voltage and current method.

For readings, the motor must be kept in a necessary time to reach the ambient temperature stability. If temperature detectors are available at the motor, the ambient temperature will be considered the average of the readings; otherwise the ambient temperature shall be verified by thermometers.

When necessary the winding resistance can be adjusted by the following formula:

++

=5.234

5.234.

winding

ratedwindingrated T

TRR

Where:R = Resistance (ohms)T = Temperature (degrees C)

Acceptance criteria:

The difference between each phase resistance must be within +/-3% from the average resistance among the three phases.

2. No Load Losses and Current

This test is used to determine the motor no-load point characteristics, no-load losses and also it is possible to ascertain motor current asymmetries.

The motor will be run, at no load and rated frequency; the voltage will be applied from 125% (rated voltage) down to the minimum value as possible.


Current asymmetry acceptance criteria: 5%.

3. Locked Rotor Current

This test is applicable for squirrel-cage induction motors.

Method 1:

During this test the rotor must be locked, then reduced voltage will be applied (05 points) at rated frequency.

The following points are measured:

Voltage Line to Line Frequency Locked Rotor Currents

With the results measured above, the locked rotor current will be extrapolated to the rated value.

Method 2:

Reduced voltage will be applied in two phases with the other phase open.The following points are measured:

Voltage Line to Line Locked Rotor Currents



With the results measured above, the locked rotor current will be calculated to the rated value divided per 0.86.


The locked rotor current tolerance is +20%.

4. Withstand Voltage Test

The dielectric test is performed to confirm the integrity of the stator insulation. A.C voltage will be applied between each phase for 60 seconds, the remaining phases and metal parts will be grounded. The A.C. hi-pot test will be carried out after running tests have been completed.

New stators - 2 times the rated voltage plus 1000 V in the primary winding. 1500 V in the space heaters and temperature detectors.

Note: High-potential testing is stressful on winding dielectric components. The voltage above is applied to stator coils during the manufacturing process. During the test at the laboratory for the second time, it is recommended that the voltage to be limited at 80% of the value stated above


Stator windings, space heaters and temperature detectors must be operational.

5. Insulation Resistance

The measurement of insulation will be made after the high-potential test by D.C. megohmmeter, at all electric circuits and accessories.

The insulation reading shall be taken 60 seconds, after starting the measuring. The instrument voltage will be selected according the rated voltage of the motor, such as the

table below:

Winding rated voltage Insulation resistance test direct voltage

< 1000 5001000 2500 500 10002501 5000 1000 2500

5001 12000 2500 5000> 12000 5000 10000

The temperature ambient and humidity during the test must be recorded.


The recommended minimum insulation resistance, in mega ohms, at 40C of the entire machine winding: 100 Mega ohms.

6. Direction of Rotation

The R S T phases from the power supply shall be connected to U, V, W (L1, L2, L3) of the motor output leads respectively.

It shall be checked, if the motor rotates in clockwise direction when viewed from drive end.


The motor running at R S T clockwise.



7. Open Circuit Secondary Induced Voltage at Standstill

On wound-rotor machines, the voltages shall be measured between all rotor terminals, with the rotor locked and its windings open-circuited and with rated voltage being applied to the stator.


The difference between each rotor voltage must be within +/-10% from the average rotor voltage among the three phases.

testing motors

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