Capacitor Question (Reassurance)

The following is a portion of an email that was in my inbox this morning. I just have to love Mondays.

Ron, we need a electrolytic non polarized large time constant capacitor to adjust amplidyne phase offsets.

I had to change the gain on the field drive boards by approx 1.2k ohms to reduce the current phase amplitudes at PI from 100 amps peak. They are closer to 80 to 84 +/- 2 amps peak but need to be adjusted.

The balance from positive to negative is also off on two phases approx 4 amps.

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My question is on the first sentence. Maybe in my old age I am forgetting basics here but aren't electrolytic capacitors always polarised? I know what they want because I remember this test from years ago. I had a little test jig with two large cans (oil filled) and a few 2 watt resistors. Someone tossed the jig in the trash at some point.

Anyway, is it just me or are all caps called electrolytic caps polarised?

Ron

Reloadron said:

The following is a portion of an email that was in my inbox this morning. I just have to love Mondays.



My question is on the first sentence. Maybe in my old age I am forgetting basics here but aren't electrolytic capacitors always polarised? I know what they want because I remember this test from years ago. I had a little test jig with two large cans (oil filled) and a few 2 watt resistors. Someone tossed the jig in the trash at some point.

Anyway, is it just me or are all caps called electrolytic caps polarised?

Ron

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Morning Ron,
You can buy non polarised electrolytic caps, often used in audio crossover units.

Non-Polarized Capacitors

Eric

ericgibbs said:

Morning Ron,
You can buy non polarised electrolytic caps, often used in audio crossover units.

Non-Polarized Capacitors

Eric

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Thanks Eric but I was questioning the terminology they used.

Ron, we need a electrolytic non polarized large time constant capacitor to adjust amplidyne phase offsets.

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My take has always been that when a capacitor is called an electrolytic capacitor it is a polarised capacitor. I guess I had my terminology screwed up. Thanks for informing me there are non-polarised electrolytic capacitors. It just somehow looked strange to me. A good mid morning back to you Eric and thank you for setting me straight.

Ron

Yes, you can get non-polarised electrolytics but most are polarised so it's probably a good idea to question this anyway.

Hero999 said:

Yes, you can get non-polarised electrolytics but most are polarised so it's probably a good idea to question this anyway.

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hi hero,
Can you please explain what you mean by this post...

The text quoted in the first post didn't completely make sense to me.

What's a large time constant capacitor?

I would question whether they know they need a non-polarised electrolytic capacitor.

Guys, thanks for the replies. I know what the sender means when he says long time constant. My only question had to do with the terminology as to a Non Polarised Electrolytic capacitor.

For some reason when I see the term Electrolytic Capacitor I tend to just assume a polarised cap and never tend to think of an Electrolytic Capacitor as being polarised.

OK, what this is about is years ago and I mean maybe 20 years ago I made a jig test box for adjusting the gain and more specific the balance of several amplifier circuits that drive a large device called an Amplydine.

Think of an Amplydine as a large motor driven AC (or it could be DC) generator device. Typically driven by a 25 to 40 HP large AC motor. Actually we use a single motor on a shaft to drive 3 such amplydine units. When I apply a signal to the field windings it amplifies that signal. The field windings are fixed and we get the outputs off slip rings. The nice part is it becomes easy to derive very slow AC signals in 3 phase. When I say slow I mean typically sub 1 Hz. General Electric was a maker of these creatures years ago. I can get 100 Volts (RMS) with currents of 90 amps. Typically I use between .8 Hz and 8 Hz (really high frequencies huh? ) So I would set up a resistor / Cap in an RC configuration and look at my signals on a scope to see any DC offset then adjust my pre amp stages for DC offset.

However, here nor there. I was just curious as to calling a capacitor an Electrolytic Capacitor since I just want to think I always viewed Electrolytics as being polarized caps. Weird huh?

Thanks
Ron