6.1 Pickup and dropout value
The test of non-pickup value, pickup value, hold value and dropout value should be carried out according to the test process drawing (Fig 1) followed. The process is uniform to both manufacturers and users. The biggest merit of the process is that the tested parameters can be repeated. It doesn’t indicate that the relay would be magnetized first and work second when the relay is used.
Generally, the pickup voltage of AC relay doesn’t exceed 85% of the rated voltage, and the pickup voltage of DC relay doesn’t exceed 75% (some are 80%) of the rated voltage. The hold voltage of DC relay is 30%-40% of the rated voltage, but the hold voltage of AC relay is a little higher than that of the DC relay. The dropout voltage of DC relay isn’t less than 10% of the rated voltage, and under limited low temperature, it isn’t less than 5% of the rated voltage. The dropout voltage of AC relay generally is about 30% of the rated voltage, and under limited low temperature, it isn’t less than 10% of the rated voltage.
6.2 Coil resistance
Coil resistance can be measured by the voltage-current means and electrobridge means. When using voltage-current means, the inner resistance of the voltmeter and ammeter should be lessened as little as possible and the measuring process should be as short as possible to avoid the rise of the coil temperature. The coil resistance is sensitive to the ambient temperature, so within 1-2 hours before the testing, the relay should be placed in the testing ambient and (had better) don’t energize the coil. The tested value “Ra”should be converted to the value under basis temperature (normally 20℃), the conversion formula is:
Ra=R0[1+a(Ta-20)]
In the formula： Ta is the ambient temperature（℃）
a is the temperature coefficient of resistance（the temperature coefficient of cupreous lead wire is 0.004/℃）
6.3 Contact resistance
When measuring the contact resistance of NC contacts, the relay is on un-energized state; when measuring the contact resistance of NO contacts, the relay is on energized state. The contact resistance can be measured by voltmeter-ammeter means. When measuring, the contact load (resistive) should accord with the regulations showed in table 7. The tested part is within 4mm to the end of the terminals. The load should be applied on the contact after it stably closes and cut off before it breaks.
The international specified load value when measuring the contact resistance (or voltage drop).
|
Application type |
Testing load（resistive） |
|
CA0 |
≤30mV ， ≤10mA |
10mA × 30mV |
|
CA1 |
30mV~6V，0.01~0.1A |
10mA × 100mV |
|
CA2 |
5~250V ， 0.1~1.0A |
100mA × 24V |
|
CA3 |
5~600V ， 0.1~100A |
1A × 24V |
| Note: When there are several application types, the criterion is the requests of the lowest application type. |
|
6.4 Insulation function
Generally, the insulation resistance is tested by mega-ohmmeter; the tested relay should be paced on high quality insulating board; the testing voltage should accord with the technical requirements of the relay; the minimum value after the voltage is applied for 2s is the measured value.
A dielectric strength test should last 1~5s under the high-tension voltage (110% of the rated voltage). If any dispute exists, the test should last 1minute under the rated voltage.
6.5 Time parameters
The measuring circuit drawing of the time parameters is showed in figure 2 followed. Other apparatus and instruments are allowed to use as substitutes, but the contact load should be resistive. To measure the operate time, release time and bounce time, the contact load should be 10mA X 6v (resistive load); to measure the stable time, the load should be 50μA X 50mV (resistive ). The distinguish ability of the instruments is 1μS.
To measure the operate time, the relay should be energized by the lower limit of the rated voltage; to measuring the release time, the energized voltage should be cut off from the upper limit of the rated voltage. The typical wave figure is showed in figure 3:
6.6 Outline dimension
The criterion of outline dimension test is the outline drawing of the relay. To measure the dimension of terminal’s position, the correct measuring position is in 3mm apart from the holder. When measuring, the outside force applied shouldn’t bring any damage to the relay.
If there are no special regulations, the measure mentioned in 6.1 to 6.5 are all carried out in normal climate conditions: The temperature is 15℃-35℃; the relative humidity is 45%-75%; the air pressure is 86.7~106.7Kpa.
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