SPDT switching time for Sudden Pressure Relay

[86ed]

Has anyone performed any testing on a Qualitrol 900 to determine the switching time for the Form-C? In other words, the time (ms) from breaking to making. Also, would this action be a function of the fault magnitude in terms of psi/sec? Not sure of the mechanics behind this contact actuating. I’m programming relay logic via 2 binary inputs to receive and process the trip and I need to set some timers to hold the rising edge and falling edge detectors that I want to use. I will contact Qualitrol but I wanted to get some feedback here first.

Thanks guys…

 

[dpc]

Not sure. These are normally used in conjunction with latching/seal-in relays, so the exact operating time of the initiating contact is generally not an issue.



David Castor

http://www.cvoes.com

 

[prc]

Qualitrol 900 is a sudden pressure relay for use in oil space.Relay actuation time depends on the rate of pressure rise in the sensor area.At 100 psi/sec, it will be 0.03 sec,10psi/sec 0.2 sec, 1psi/sec:3 sec. Pressure rise in oil depends on the magnitude of arc current inside and the distance of fault point from the relay sensor.

 

[stevenal]

86ed is looking for contact transfer time, not actuation time.

http://www.qualitrolcorp.com/uploadedFiles/Siteroot/Products/AP-P06-01L-01E_900_910.pdf

Two curves are provided, so I'm guessing one curve is for open and the other for close. Looks like it is pressure rise dependent with delta t going to infinity for slow pressure rise rates.

 

[prc]

stevenal,what is the difference between the contact transfer time and actuation time. What we are expecting of SPD relay is that it should trip the transformer when pressure rise is high.

I thought of the two graphs as the dispersion in relay actuation time.

 

[86ed]

stevenal, is correct. I was looking for the contact transfer time.

However, I contacted Qualitrol and they said the two curves actually represent an operating region rather than the make vs. break actuating time curves.

In the end…according to Qualitrol…2 cycles is the transfer time from break to make and it is not a function of psi/sec.

 

[stevenal]

prc,

Actuation time would be the time from initial pressure rise to the time the relay contacts do something. I'm a bit vague at the ending time, since I don't which set of contacts Qualitrol uses. But draw the region wide enough and it will cover both sets of contacts.

Transfer time is the time from the opening of the NC side of the switch to the closing of the NO side.

 

[prc]

Thank you stevenal.One more query, may be elementary-why the transfer time is of any significance in this case?I thought closing of NO contacts will trip transformer and any reenergisation will be after thorough check and testing.