Varistor

[discusted electrician]

When experiencing transient surges, will the use of a varistor to solve this problem be considered a short fix or will it solve the problem over the long haul?

 

[petersonra]

When experiencing transient surges, will the use of a varistor to solve this problem be considered a short fix or will it solve the problem over the long haul?

varistors are a pretty good choice for dealing with transients. however, IMO, the "best" solution is to have some kind of surge protector at the service point, and at all sub-panels. common varistors just don't have the capacity to absorb enough energy as sometimes comes down the line.

 

[dereckbc]

When experiencing transient surges, will the use of a varistor to solve this problem be considered a short fix or will it solve the problem over the long haul?

Fix is the wrong word, you cannot fix transients, all you can do is attenuate or supress them. The only way to fix them is at the source of what generates them which is really impossible. The only ture way to completely eliminate them is to power sensitive equipment with an industrial grade dual conversion UPS.

Otherwise your best defense is a Class C TVSS, UL-1449 listed device built into the main switch gear followed up by Class B devices in branch panels, and Class A at the point of use in sensitive equipment.

 

[megloff11x]

What are your transients?

I've had outstanding results with VFD run motors when using the new VFD multi-layer shielded insulation cables. These cables really shield well at all frequencies.

If your transient energy exceeds the TVSS rating, it will blow or be weakened.

Matt

 

[nc5p]

You would do well to determine the source of the transients. They do not always originate in the supply, but can come from loads as well. When clamping a transient the device doesn't dissipate all the energy but reflects much of it back to the source. Add inductance (even wiring is enough) and you can transfer the damage to another location in the power system. TVS devices do have a limited life if continually clamping transients.