K-D1A Leach International, K-D1A Datasheet - Page 6

• Manufacturer Part Number: K-D1A
• Description: Electromechanical Relay 4PDT 12A 28VDC 290Ohm Flange Mount
• Manufacturer: Leach International
• Type: Non Latching Relayr

Specifications of K-D1A

• Contact Arrangement: 4PDT
• Coil Current: 96.55 mA
• Mounting: Flange Mount

Most relay parameters are specified as maximum values over the rated temperature range of the specific relay. Users often
find that key parameters differ significantly at ambient temperature (20-25°C) and sometimes fall into the trap of specifying
their system around these ambient parameters. Additionally the actual temperature experienced by the relay can be far in
excess of existing ambient temperatures due to the heat generated by the coil current and the contact load. Figure 1 is the
summary of temperature effects on relay electrical characteristics.
The following formulas are sometimes useful in calculating the effects shown above.
1. Change in coil resistance due to change of ambient temperature can be calculated by the following formula.
"Rule of Thumb" : For each 10°C change of temperature, coil resistance will change approximately 4%.
2. High and low temperature pick up voltage:
Date of issue: 6/00
Temperature
Increase
Decrease
Application notes
Resistance
UP
DOWN
K
2
= Coefficient of correction found on the graph in Fig. 2 at T
RELAYS AND TEMPERATURE VARIATIONS
Current
DOWN
UP
Where: R = Coil resistance at given temperature
Where: E
E
R
2
T = °C Ambient temperature
1
R = R
20
= Pick Up Voltage at T
= Pick Up Voltage at 20°C
= Coil resistance at 20°C
Operating
Voltage
UP
DOWN
20
E
[1 + .0039 (T-20)]
2
Fig. 1
- 15 -
= E
1
K
2,
Release
Voltage
UP
DOWN
2
temperature
Operate Time
UP
DOWN
2
Release Time
UP
DOWN
N°102
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