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Oil-Filled Pressurized Relay Sticks ON and Burns Up (Why?)

B

Bookmarkw

Jan 1, 1970
0
I've got a mechanical (i.e., not solid state) relay I'm using in pressurized
oil. Some boards work fine. Some, though, stick ON under pressure. Some burn
up. Holes are drilled in the package to allow oil in (to prevent the package
from collapsing.) The voltage connected to the relay is 240VAC.

Can anyone suggest a cause/solution?

Thanks!
 
R

Robert Baer

Jan 1, 1970
0
Bookmarkw said:
I've got a mechanical (i.e., not solid state) relay I'm using in pressurized
oil. Some boards work fine. Some, though, stick ON under pressure. Some burn
up. Holes are drilled in the package to allow oil in (to prevent the package
from collapsing.) The voltage connected to the relay is 240VAC.

Can anyone suggest a cause/solution?

Thanks!

You did not indicate whether that 240VAC is on the coil or the
contacts or both.
In any event, check that the peak load current handled by the contacts
is well under the rating.
Also, check if the load is inductive and verify the proper snubber is
across the contacts.
Next, add a thin piece of paper between the pole and the armature;
this insures a magnetic gap when closed, and increases the drop-out
voltage and prevents magnetic "sticking", especially with DC on the coil
(Note: the added gap has zero effect on pull-in voltage).
 
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