Test report, January, 2008
J. Mickowski, B.Eng. MS Computer Science
Analysis: The construction of the GEI AR4-1 relay was compared to the Omron G8HN equivalent, and a vibration test was conducted to determine whether either exhibited contact bounce.
Both of the relays passed the vibration test. Neither relay showed any contact bounce over the frequency range for equivalent RPM's from 1,000 up to 10,000. The NC contact remained in contact throughout the test for both relays.
The construction comparison is as follows:
|
GEI |
Omron |
| Moving contact mat. |
Silver alloy |
Silver alloy |
| NC contact mat. |
Copper |
Silver alloy |
| NO contact mat. |
Copper |
Silver alloy |
| Moving contact dia. |
0.085/0.083" |
0.099/0.098" |
| Terminal material |
Plated Brass |
Plated Copper |
The magnetic coils appeared almost identical. The Omron coil appeared to contain more copper. Both had inductive voltage spike suppression resistors.
The thermal conduction path for contact heat was better for the Omron, as it used heavier cross section conductors for the contacts through to the terminals, especially on the NO contact, which is used for starting. The additional 1 gram weight of the Omrons is consistent with this.
In comparing the manufacturer's specifications, the Omron is rated higher than the GEI in every category except steady load current. These include inrush current, maximum initial contact voltage, high frequency vibration, and operating temperature.
Omron also includes reliability testing specifications, shock, humidity, inductive load reliability, and overload inrush testing at 100 amp and 20 amp steady load to 300,000 cycles. GEI does not provide corresponding specifications.
Conclusion: The GEI is rated at 25 amps for the NO contact and 20 amps for the NC, whereas the Omron is rated at 20 and 10 respectively. In my opinion, there is no basis for the higher contact ratings claimed by GEI. If anything, they should be lower than Omron's ratings when based on the same objective criteria. In further support of this, the inrush current capacity of the NO contact specified by GEI is 25 amps, as compared to 60 specified by Omron.
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