Help me identify an unmarked electrical component.

[rocketman768]

I have a malfunctioning centrifuge: it keeps blowing the fuse. Being an EE, I decided I'd take it apart and fix it. Immediately after the fuse, there's a mysterious unmarked electrical device:

The 3 leads nearest the camera are for the neutral wire coming in, the hot wire from the fuse, and the ground wire. On the other side there are two terminals for a white a black wire that go somewhere else (I can't tell yet).

My first thought is that it's conditioning the incoming AC in some manner, but since it has no markings, I can't just google it. So, can anyone identify this thing?

 

[rcbishop]

That looks to be a line filter. Its purpose is to let the 60Hz AC pass through, but block higher frequencies. Since it's a centrifuge, I'm guessing the filter is there to prevent noise from the motor drive from causing interference to other stuff you have plugged in.

Is it blowing the fuse the second you power it on, or does it run for a while first?

 

[cyberwollf]

crack it open

 

[rocketman768]

That looks to be a line filter. Its purpose is to let the 60Hz AC pass through, but block higher frequencies. Since it's a centrifuge, I'm guessing the filter is there to prevent noise from the motor drive from causing interference to other stuff you have plugged in.

Is it blowing the fuse the second you power it on, or does it run for a while first?

Cool, thanks for identifying it.

No, the fuse only blows when the motor starts, so it's something either in the motor or the subcircuit attached to the motor, but unless it's the motor itself, I don't know if I can track the problem down because otherwise the bad component is on the circuitboard somewhere. Got any tips?

 

[cyberwollf]

You can check the ohms of the moter to ensure the windings didnt get shorted or something

 

[gingerdawg]

Are you sure it's not a motor start capacitor?

 

[rocketman768]

Are you sure it's not a motor start capacitor?

No, but this thing supplies everything in the centrifuge, so I don't expect that it's a motor start capacitor.

 

[ClaudiusB]

Are you sure it's not a motor start capacitor?

Based on his description this is a line filter.

The 3 leads nearest the camera are for the neutral wire coming in, the hot wire from the fuse, and the ground wire. On the other side there are two terminals for a white a black wire that go somewhere else

Cheers,
ClaudiusB

 

[rocketman768]

ClaudiusB, you are right.

I coaxed the schematic for the centrifuge out of the manufacturer, and the unit is labeled as an interference filter. Now...to the fixin'