Why are my terminals not marked on my capacitor?

[dana198]

TL;DR Summary

I recently purchased a capacitor for my air compressor but the terminals are not marked by any means , i have never seen that before can anyone tell me what i should do ? Does it matter ?

 

[tech99]

I think is is a bi-polar type intended for AC, so polarity does not matter.

 

[AZFIREBALL]

The marking of capacitor terminals is an antiquated practice that is no longer necessary.

Capacitor terminals at various times in the past were designated with terms such as: In and Out, Up and Down, Plus and Minus, + and -, Charge and Discharge, etc. These terms where ambiguous to the neophyte to say the least.

As you know, today’s electric bolts consist mainly of poles and holes and are much more sophisticated than they once were. They therefore, are able to decipher which terminal is which, without the need for overt designations. And due to the fact the frequency of DC is much lower today than it once was; along with today’s environmental need to always be politically correct, the terminals must be capable of being used without prejudices or discrimination.
Then again, I might be wrong.

[Humorous post deprecated by the Mentors]

 

[Baluncore]

It is a 250 VAC capacitor. It is 100 uF. It has symmetrical construction because it is for use in an AC circuit. It is not polarised and can be connected either way.

It could be the start or run capacitor for a single phase AC induction motor.
Is that the original or a replacement capacitor ?
What was the voltage rating and capacitance of the original capacitor ?
What is your supply voltage closest to; 115 VAC or 230 VAC ?
What is the HP or kW rating of the motor ?
Is there another capacitor on the motor, what specs ?

 

[Borek]

The marking of capacitor terminals is an antiquated practice that is no longer necessary.

Nope. Especially in the case of electrolytic caps it is crucial to connect them following polarity:

 

[phinds]

The marking of capacitor terminals is an antiquated practice that is no longer necessary.

Capacitor terminals at various times in the past were designated with terms such as: In and Out, Up and Down, Plus and Minus, + and -, Charge and Discharge, etc. These terms where ambiguous to the neophyte to say the least.

As you know, today’s electric bolts consist mainly of poles and holes and are much more sophisticated than they once were. They therefore, are able to decipher which terminal is which, without the need for overt designations. And due to the fact the frequency of DC is much lower today than it once was; along with today’s environmental need to always be politically correct, the terminals must be capable of being used without prejudices or discrimination.
Then again, I might be wrong.

Is this whole post supposed to be a joke?

 

[Baluncore]

Is this whole post supposed to be a joke?

Probably. Maybe written with excessive Christmas lubrication.

 

[hutchphd]

Is this whole post supposed to be a joke?

If a joke it is in the same classification as the "inject chlorox for COVID" variety. Hopefully fueled by lubrication and not dementia.
But to reiterate:

The marking of capacitor terminals is an antiquated practice that is no longer necessary.

This is completely and totally incorrect. Many modern capacitors are polarized and failure to recognize this can be disastrous.

/

 

[jrmichler]

To the OP: Your capacitor is clearly marked 250 VAC. That is the correct rating for a capacitor intended for use in a 120 volt AC application, such as a motor start or motor run capacitor. Posts #2 and #4 are correct.

To everybody who wants to be helpful: This thread is about motor capacitors. It is not a general thread on electrolytic capacitors. Please stay on topic. Also realize that the OP is clearly not an electrical engineer, so this is not an appropriate thread for EE jokes such as Post #3.

 

[Baluncore]

Your capacitor is clearly marked 250 VAC. That is the correct rating for a capacitor intended for use in a 120 volt AC application, such as a motor start or motor run capacitor.

A motor START capacitor will be rated at close to the motor voltage. A motor RUN capacitor needs to be rated for about 1.8 times the motor voltage.

 

[sysprog]

A motor START capacitor will be rated at close to the motor voltage. A motor RUN capacitor needs to be rated for about 1.8 times the motor voltage.

Why wouldn't that be the other way around?

 

[AZFIREBALL]

To the OP: Your capacitor is clearly marked 250 VAC. That is the correct rating for a capacitor intended for use in a 120 volt AC application, such as a motor start or motor run capacitor. Posts #2 and #4 are correct.

To everybody who wants to be helpful: This thread is about motor capacitors. It is not a general thread on electrolytic capacitors. Please stay on topic. Also realize that the OP is clearly not an electrical engineer, so this is not an appropriate thread for EE jokes such as Post #3.

Sorry for the injudiciousness. Too much Christmas Eggnog!

 

[Baluncore]

Why wouldn't that be the other way around?

Maybe you can explain why you think I put it backwards.

The quick way to identify a run cap is from the higher voltage rating. I believe it is because with varying loads, the run capacitor can react with the winding inductance to generate higher voltages in the series circuit.

 

[sysprog]

Maybe you can explain why you think I put it backwards.

The quick way to identify a run cap is from the higher voltage rating. I believe it is because with varying loads, the run capacitor can react with the winding inductance to generate higher voltages in the series circuit.

That makes sense to me $-$ I was thinking of initial current draw being greater on start $-$ 😌

 

[berkeman]

Is this whole post supposed to be a joke?

Yes, it has been deprecated...

 

[berkeman]

Sorry for the injudiciousness. Too much Christmas Eggnog!

You should have included the [ humor ] [ /humor ] tags...