ARISTO STANDARDS

  • 36 Series Backelite Body

    Standard Rating For 36 Series
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  • 37 Series Aluminium Body

    Standard Rating For 37 Series
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  • 38 Series Single Can

    Standard Rating For 38 Series
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  • Specifications For Electrolytic Motor Start Capacitors

    DEFINITION :
    1 A power capacitor which provides a leading current to an auxiliary winding of a motor and which is switched out of circuit once the motor is running.

    ARISTO range of aluminium Electrolytic Motor Start Capacitors specifically designs for a.c. operation, which help to start the motor by providing a leading current to the auxiliary winding. The capacitor is not permanently connected to the winding of the motor and is switched off after starting, usually automatically. Capacitors for this application are designed for intermittent duty only, and must be capable of withstanding a.c. voltage applied to the motor during starting.

    The current shall be calculated as follows :

    I = 2 * 3.147 * fv * C / 106 = C * V / 3180
    Where,
    C = Capacitance in microfarad,
    I = rms value of current in amperes,
    f = frequency in hertz,
    V = rms value of test voltage in volts.

    Intermittent Operation
    Operation in which periods with the capacitor energized are followed by intervals during which the capacitor is unexercised.

    Starting Operation
    A special type of intermittent operation in which the capacitor is energized for only a very short period while the motor is accelerating to rated speed.

    Rated Duty Cycle
    A rated value indicating the type of intermittent or starting duty for which a capacitor is suitable. It is specified by the duty cycle duration, in minutes, and the percentage of the time during which the capacitor is energized.

    Duty Cycle Duration

    Total time of one energized and one unenergized interval during the intermittent operation.

  • Quality Requirements And Tests

    Test Conditions
    Unless otherwise specified for a particular test or measurement, the temperature of the capacitor dielectric shall be in the range +15° C to 35° C range and shall be recorded.

    Type Test
    Type tests are carried out by the manufacturer under the supervision of a proper authority, which will issue a certified record and/or type approval. ARISTO follows the European
    Standard EN 60252-2 for type test.

    Routine Test
    Routine tests shall be carried out by the ARISTO on every capacitor before delivery. The norms of European standard EN 60252 will be followed.

    Temperature Limits
    The preferred minimum and maximum permissible capacitor operating temperature shall be as follows:
    Minimum : – 30° C, -25° C, -10° C, – 0° C
    Maximum : +55° C, +70° C, +85° C, +100° C
    Operating temperatures may be adopted on agreement from purchaser. Normal production shall be with temperature limits -25° C or -30° C and +70° C.

    Damp Heat Severity
    Capacitor is retained without application of voltage and no measurement shall be taken during the test. The severity shall be 21 days. After the test keeping capacitor under standard atmospheric condition for minimum one hour (not more than two hrs.), the capacitance and tan delta is observed. Capacitance should not differ by +/- 10% and tan delta should not exceed more than 0.20.

    Visual Examination
    Capacitor shall be visually examined and checked for finish and marking.

    Voltage Test
    Capacitor shall be subject to an ac voltage test. The test shall be carried out with stabilized voltage at a frequency as near as possible to the rated frequency. Voltage application between terminals should not be more than 2 seconds. The test voltage may be increased by 10%.

    Capacitance Measurement
    Capacitance shall be determined by measuring the current through the capacitor at rated voltage and rated frequency of the capacitor. The rated voltage should not be applied for more than 3 seconds. Test should be carried out at room temperature. (Range from 18° C to 30° C).

    Tangent Of Loss Angle
    The measurement of tangent of the loss angle should be in the temperature range from 18° C to 28° C. Tan delta should not exceed 0.15 after endurance and damp heat test; a limit of 0.20 shall be applied.

    Dimensions
    Dimensions of container, terminals, cable and the clearances between creep age distances shall be checked.

    Sealing Test
    Capacitance should be positioned most likely to reveal leakage at a temperature +5° C higher than the maximum permissible capacitor operating temperature for minimum 4 hours and cooling time 4 hours. The temperature should be increased uniformly. No leakage should be observed after 8 hours cycle mentioned above.

    Endurance Test
    The capacitor should be mounted in a chamber in which heated air is circulated in such a way that capacitors shall have uniform heat. No heating shall take place through radiation. The temperature of the capacitor should reach the stated temperature with a tolerance +/-2°C. The test time is computed from the moment of exercitation. The maximum permitted variation of capacitance compared to the value measured before the test, and the maximum permitted individual values of tangent of the loss angle should not exceed 0.20, and the capacitance variation up to 15%.

    2.4.0 Creep Age Distance & Clearances
    Distance between the different polarities should be 6 mm up to 250 VAC, and 12 mm for higher voltage.

    Voltage Test To Case

    Voltage of 2000 VAC is applied between capacitor leads and the outer casing.

    Insulation Resistance
    The insulation resistance shall be measured between terminals connected together and the outer casing.

    Shelf Life
    Capacitor can be stored for one year without damage. The capacitor shall be recharged by applying rated voltage for 2 – 3 seconds. This may be repeated 2 – 3 times.

    Destruction Test
    Capacitor is directly applied with its rated voltage continuously and the bursting time shall be noted. The mode of bursting and formed gas passing is observed. At the time of bursting the formed gases should be passed through the vent hole of the capacitor.