Bifurcated Relays - Benefits for microprocessors : LUSENET : Elevator Problem Discussion : One Thread


We have had so many inquiries about 4PDT bifurcated contact relays, and their benefits to Microprocessors Units, that we decided to put out this information sheet.

 Reduces contact bounce  When a relay contact engages, the contact has a tendency to bounce. In a microprocessor environment, because of the processors sensitivity, this could cause a false reading. A bifurcated contact reduces/eliminates this problem.

 Increases reliability  Because there are two contact leafs, one leaf will engage first then the second when current is applied. This reduces the wear of the contacts that in turn increases the overall life cycle of the relay.

 Assists in switching - When the circuit switching is being performed in a low voltage/current environment, the bifurcated contacts conduct the switching more efficiently. If you have 110/120 voltage coming in and the circuit switching is being performed in a 12/24-voltage range, the bifurcated contacts enhance and assist in this procedure.

 Summary - If you have 110/120 voltage coming in and the switching is being preformed in the same voltage, standard contacts are recommended. However, if any of the above situations are a concern, bifurcated contacts may fix some nagging reoccurring problems.

Due to the increase of microprocessors in the elevator industry, bifurcated relays are becoming more common. The problem has always been cost and availability. They are usually special order items and are cost prohibited. We have seen the price of a bifurcated relay priced as high as 27.00 for one relay. Because of the special ordering and the cost, most elevator companies will not consider using bifurcated relays regardless of its advantages.


Again, this feature seems to be overlooked by many companies and we feel the need to clarify.

BI-Polar - Several relay manufactures produce the same general-purpose 4-pole relay and when put next to each other, they look the same. However, some relay manufactures have the positive input on the 14th pole of the relay while others have their positive input on the 13th pole. With this in mind, engineers design their boards to operate with that brand relay and the purchasing department is told only this brand relay will work on their boards. This creates a propriety situation that no company desires.

Why Gold Flashed Contacts? This one is easy to answer. Gold is a better conductor of electricity then silver. Most relay manufactures offer silver as the standard and gold is special order.

Cyberdyn Systems has solved all of the above problems. All of our relays are BI-Polar. This means our relays will except a positive input on the 13th or 14th Pole. Regardless of the manufacture, our relay will function and the LED will light. This is a great feature for companies that service several different make and model elevator controllers on their route. In addition, all of our relays come standard with gold flashed contacts for better conduction. Also, our bifurcated models, with gold flash, are priced lower than our competitors basic model.

Cyberdyn Systems understands the elevator industry concerns and answers with a solution. We maintain both Bifurcated and Standard Contact BI-Polar relays at our facility available for immediate delivery: Bifurcated DC 12V $2.52 Bifurcated DC 24V $2.52 Bifurcated DC 110V $2.52 Bifurcated AC 120V $2.63 Standard Contact DC 48V $2.52 Standard Contact DC 110V $2.28 Standard Contact AC 120V $2.63 Standard Contact AC 240V $2.57

Standard Features on our four poles: BI-Polar, LED indicator, ARC Barrier, Gold flashed contacts, 5 Amp rating, CSA/UL, Color coded coils for quick voltage identification.

Fixed pricing and no minimum buy.

Call or visit our web site at http:\\ Phone 954-428-9939.

We hope the above explanations will help clarify these features.

-- Robert Sessanna (, May 02, 2000

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