Definition of Specifications
Bounce Time - The time interval between when the contact first makes, and when the last contact make occurs.
Coil Hi-Pot - The minimum voltage which the relay coil terminals will isolate when the relay is properly mounted.
Coil Resistance - The DC resistance, in ohms, of the coil at 25°C.
Contact Arrangement - All Kilovac relays are one of the following:
- single pole single throw (SPST)
- single pole double throw (SPDT)
- double pole double throw (DPDT)
- four pole double throw (4PDT)
Contact Capacitance - Contact capacitance is measured either between open contacts or between contacts and ground. Measurements are made per MIL-STD-202, Method 305, at 1 kHz.
Contact Form All Kilovac relays are one of the following:
- Form A: SPST-Normally Open
- Form B: SPST-Normally Closed
- Form C: SPDT
- Form 2C: DPDT
- Form 4C: 4PDT
- Form P: SPST-Latching
- Form R: SPDT-Latching
- Form X: SPST-NO-Double Make
- Form Y: SPST-NC-Double Break
Contact Resistance - In vacuum relays, the resistance of closed contacts is measured as voltage drop across contacts carrying 1 amp at 6 Vdc. Measurement is made in accordance with MIL-R-83725, SAE ARD 50031, or MIL-R-6106. In gas-filled relays, 1 amp at 28 Vdc is used to measure contact resistance. "Kelvin" connections should be used to obtain accurate readings.
Continuous Current - The maximum current that can be carried by the closed contacts of the relay for a sustained time period. This specification
is determined by measuring the resis-tance heating effect on critical relay components and must be derated at RF frequencies.
Dielectric Strength - The maximum allowable AC rms voltage (50 or 60 Hz) which may be applied between two test points, such as the coil and case or current carrying and non-current carrying points, without a leakage current in excess of 1 milliamp.
Drop-out Voltage - Thevoltage at which all contacts return to their "normal", unoperated positions. (Applicable only to non-latching relays.)
Insulation Resistance - The minimum allowable DC resistance between two test points, such as the relay contacts and the coil, or contactsand case at a specified voltage, usually 500 Vdc.
Hold Voltage - The lowest voltage that can be applied without any change in state of the contacts from their energized position. This is just above the maximum drop-out voltage. Leakage Current The rms current conducted by the output circuit of the relay at maximum rated voltage with the contacts open.
Load Life - The minimum number of cycles the relay will make, carry, and break the specified load without contact sticking or welding, and without exceeding the electrical specifications of the device. Load life is established using various methods including Weibull probability methods.
Load Life, Rated Resistive - The voltage and current encountered by the contacts when opening and/or closing. To be considered a resistive load,
the inductance in the test circuit shall not exceed an L/R ratio of 1 x 10 -4 . Load ratings are established using various methods including Weibull analysis.
Mechanical Life - This is the number of operations which a relay can be expected to perform while maintaining mechanical integrity. Mechanical life is normally tested with no load or voltage applied to the power contacts and is established using various methods including Weibull analysis.
Operating Temperature Range - The ambient temperature range over which an unmounted relay is specified to operate.
Operate Time - The time interval between the coil energization (nominal coil voltage) and the closing of all normally open contacts. This includes time for the coil to build up its magnetic field (a significant limiting factor) and transfer time of the moveable contact between station-ary contact(s), and bounce time after the initial contact make. All Kilovac relays, except "AP" and "PD" power switching products include bounce time.
Graphic Representation of Operate Time
Figure 10. * Kilovac "PD" products do not include contact bounce time.
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