Delta-wired phase correction capacitors / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Delta-wired phase correction capacitors

Move Thread

LAN_403

Shrad

Mon Jan 09 2012, 03:01PM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

Hi all,

I have acquired right now a bank of two 180ÂµF 440V delta phase correction capacitors and the same bank of 80ÂµF 440V capacitors

Is there another way to use them than power factor correction?

I couldn't think of any use as they are delta wired, I'm so sad they are not wye grounded as it would have been killer caps for a small high voltage SSTC

If you have an idea, please tell me so, otherwise they will be being sold shortly either here or on fleabay

Pics to come tonight!

radiotech

Tue Jan 10 2012, 01:41AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

Just ground on terminal to the case. How do you know what capacity they are?
Are they marked in KVARS ? Is the case marked non-PCB?

Shrad

Tue Jan 10 2012, 10:46AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

they are some MKK400-D-20 and MKK400-D-12 if I recall

they should be 12.5kVAR and 25kVAR but I don't have them in sight... capacity is marked on the stickers. I should receive more of the bigger ones shortly, so if someone is interested, I might sell them for a decent price

Shrad

Fri Jan 13 2012, 09:31AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

if someone is interested, or has any idea about how to reliably use those in DC, please tell me

I'll be able to get more than 20 of those caps, as well as some 10kVAR 400VDC single phase ones (more than 50 of those, which I might keep)

Xray

Sat Jan 14 2012, 05:37AM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

Shrad wrote ...

Is there another way to use them than power factor correction?

Well, sure. If you can get to the terminals, then I believe that you could use them just like any other capacitor of the same ratings. But you are going about it bass-ackwards! Instead of stating, "I have this project that I'm considering building, so tell me what type of capacitors I would need for it", you are essentially stating, "I have a bunch of capacitors, so tell me what I could do with them." And that's not unusual here in this forum. Many times I've read posts from guys who'd found a flyback and then they ask, what can I do with it!

wrote ...

I couldn't think of any use as they are delta wired, I'm so sad they are not wye grounded as it would have been killer caps for a small high voltage SSTC

If you have an idea, please tell me so, otherwise they will be being sold shortly either here or on fleabay

Pics to come tonight!

Yes, it would be helpful if we could see what they look like. I'm wondering if you could somehow disassemble them in such a way that enables you to access the terminals without destroying them. Then, of course, you'd be able to disconnect the delta configuration and use them as individual caps.

Sulaiman

Sat Jan 14 2012, 07:57AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

I expect those capacitors consist of a single roll of three electrode foils
and three dielectric foils (possibly in two series sections)
which would be impossible to separate into three single capacitors.
( let Cph = capacitance per phase-phase, e.g. 80 uF)
Each Cph can have ac and/or dc up to a peak of sqrt(2) x Vphase

Connecting to any two terminals you can use each unit as a
single capacitor of 1.5 x Cph (120uF)

Shorting two terminals together would give 2 x Cph (160uF)

or use the unit in a voltage doubler ?
e.g. like this

with the third Cph being across the dc.
e.g. 110 Vac to 300 Vdc

Or as the capacitors for a half-bridge switcher.

P.S. For switcher use I think that
The dielectric is probably polypropylene so the main limitations of these capacitors will be the effective series inductance and current rating.

Shrad

Mon Jan 16 2012, 08:34AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

Sulaiman you're the man!

The capacitors are effectively of that type I believe, as they are encapsulated in a rigid can and three terminals come off the top

They also have a security feature which enables the top to pop off when overpressure or overtemperature is reached, disconnecting the terminals, and this system is surely impossible to dismantle non-destructively

Shorting is something I'd try to avoid as capacitive coupling should still occur and big losses would be a pain to cope with.

The voltage doubler, though, would be really nice as the resistance and current ratings are nice (don't know about inductange but given the ratings it should be nice enough)

See the ratings :

How would you use it in a switcher configuration?

EDIT: I just simulated a Villard cascade and it seems to be quite nice... outputting a great amount of current for a small amount of components and work

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob