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Type LK capacitors offer unusually good electrical characteristics, coupled with very small size. They are designed for twice the life of MIL-C-25D capacitors (see life characteristics) and will meet or exceed the requirements of characteristic E. These are not QPL listed.
Type LK capacitors are specifically designed for filter, bypass and coupling applications in the low audio frequency range. The CP70 style container and internal construction permit operation in any position. Glazed steatite bushings are used, and in the voltage ranges of 2000 and greater, steatite is the electrical insulation in the terminal assembly. The threaded stud terminal is supplied with nut and solder lug. The whole assembly is hermetically sealed.
Applications. While type LK capacitors are designed primarily for filter , bypass and coupling applications in the low audio frequency range, they may be used advantageously in the following applications.

Consult Plastic Capacitors, Inc. engineering staff for your specific applications.


Temperature Range is minus 55°C to 105°C. Rated nameplate voltage is from minus 55°C to 85°C.
Temperature Coefficient: Capacitance change over the temperature range is indicated by the limiting curves in graph "T vs. C".
Capacitance Tolerance standard is 10%. Also available are tolerances of 5% and 2%. Nominal value of capacitance of 1 mfd. or less is measured with 1000 CPS applied to the bridge and 60 CPS for nominal values greater than 1 mfd.
Life Characteristics: Definition of Groups I, II and III are included in life test Paragraph.

- Group I capacitors are rated for 2,500 hours life at 85°C and 17,000 hours life at 50°C. For 10,000 hours life at 85°C derate to 75% nameplate voltage rating. For 2,500 hours life at 105°C derate t1,250 hours life at 85°C, 8,500 hours life at 50°C. For 2,500 hours life at 85°Co 85% nameplate voltage rating.
- Group II capacitors are rated for  derate to 85% nameplate voltage rating. For 10,000 hours life at 85°C derate to 65% nameplate voltage rating. For 2,500 hours life at 105°C derate to 70% nameplate voltage rating. (see life test for capacitor groupings.)
- Group III capacitors are rated for 500 hours life at 85°C, and 3,500 hours life at 50°C. For 2,500 hours life at 85°C derate to 70% nameplate voltage rating. For 10,000 hours life at 85°C derate to 55% nameplate voltage rating. For 10,000 hours life at 50°C derate to 80% nameplate voltage rating.
Dielectric Resistance (parallel resistance) is indicated by the curve R vs. T. This curve expresses limits with nameplate voltage applied and 2 minute electrification time. Limitations 100³ megohms x mfd. or 100³ megohms whichever is less at room temperature.
Power Factor is variable and is function of temperature and frequency. Refer to graph, "Power Factor vs. Temperature".
Ripple. The peak ripple voltage plus the DC voltage should not exceed the nameplate voltage. Acceptable peak to peak ripple voltage in percent OT nameplate voltage follows.

PHYSICAL DESCRIPTION

Type LK capacitors are oil-impregnated, oil-filled and are hermetically sealed.
Case is terne-plate or hot-tinned steel.
Finish consists of a prime coat and finish coat of synthetic enamel, grey in color.
Terminals are mounted on glazed steatite bushings. Neoprene gaskets or solder seals are used to effect the hermetic seal and a nut and solder lug are provided as part of the terminal assembly. Steatite is used as the insulation between the terminal post and the case for all voltages greater than 1000. All terminal bushings are oil-filled.
Dielectric is a combination of polyester resin film and the finest grade Kraft capacitor tissue.
Impregnant is a highly refined, purified and inhibited mineral oil with a flash point greater than 145°C when measured per method 110.3.4 of Specification VV-L-791.
Brackets: Footed brackets are supplied at no charge. A nominal charge is made for spade bolt type brackets. These may be ordered only with capacitors.
Mounting Position: All type LK capacitors will operate satisfactorily mounted in any position.
Test Voltage. Terminal to terminal for capacitors rated through 20KV, one minute at room temperature with 200% rated voltage applied. For rated voltages grater than 20KV, 150% rated voltage for two minutes at 150% rated voltage for two minutes at room temperature.
Terminal to case, same as above, but plus 1000 volts.
Test voltage shall be applied and discharged through  resistance of at least one ohm per rated volt but need not be more than 5000 ohms.
Flashover: The capacitor terminals will withstand 125% rated nameplate voltage without flashover at a pressure of 3.4 inches or mercury, equivalent to 50,000 feet altitude. This applies only to nameplate voltage of 5000 or less. Rated nameplate voltage of 6000 or more will withstand 125% rated nameplate voltage at a pressure of 20 inches of mercury, equivalent to 10,000 feet altitude.

ENVIRONMENTAL TESTING

Life Test will be conducted at 85°C for 500 hours. One failure of 24 so tested will be permitted. Voltage applied will be according to the following table:
    I    0-50 watt seconds - Less than 12 mfd., 140% rated voltage
   II    12 mfd. or more - 120% rated voltage
    I    51-200 watt seconds - 4 mfd. or less, 140% rated voltage
   II    5 mfd. or more, 120% voltage
   II    201 or over watt seconds - 2 mfd. or less, 120% rated voltage
  III    Over 2 mfd., 100% rated voltage
Temperature and Immersion cycling shall be conducted per requirements of MIL-C-25D.
Moisture Resistance shall be conducted per requirements of MIL-C-25D.
Corrosion or Salt Spray test shall be conducted according to the 100 hour requirements of MIL-QQ-M-151A.
Vibration and Shock tests may be performed per MIL-C-25D or per MIL-E-5272 (any method).
How to Order. Check listing for capacitance and voltage. Note that more than one container size is often available. Standard capacitance tolerance is ±10%; for closer tolerances use basic part number assigned and add a dash (-) plus the tolerance required i.e., 5 or 2 for 5% or 2%.