Old Motor Run Capacitors

[ka7niq]

I was surfing and found This http://www.surpluscenter.com/item.asp?item=22-1161&catname=electric

They have used pulls, some new ones, and some buyouts. They are quite inexpensive, so thought I would give them a try in my old E/V Sentry III's. if tey dont work out, at these prices, I could probably re sell them on ebay ? I dont know if these are old paper in oils, polys, or mylars in some kind of liquid besides PCB oils ? I bought on weight alone, because they seem to have several choices in most capacitance ranges. I figured the more weight, the more liquid or oil, but What do I know. You spend your money, you take your chances. I have never tried motor run capacitors before, one of the few that I have not tried, but they seem to be popular with some. Perhaps they will suprise me, cheap thrills. if they do sound good in my speakers, how do you mount them ? My speakers have backs that are split in two sections, I have stands underneath the backs to hold them when they are taken off. This allows me to roll caps at will, and listen, though the bass is compromised by having the top back of speaker open. I plan to set em on tyhe board, and wire em in, see how they sound. IF they sound good, I will have to rig some kind of way to hold them to the crossover board. There is plenty of room for them in the E/V Sentry II crossover. Anyone recognize these capacitors, and know what kind they are ?

[Al Klappenberger]

Don't use there in any of my designs!

AL K.

[BEC]

Most of those you find will be polypropylene in oil. If made well they will have very low ESR. The best I have used were made by either GE or Aerovox. I used the GE ones in my crossover work as long as GE was building them.

Bob Crites

[Deang]

I don't trust those people -- it looks like they're selling stuff.[]

Seriously though, they don't tell you anything about them except that they're used and have been pulled from equipment. They don't tell you what they are, how old they are, what kind of equipment they were pulled from, or the environmental condition the equipment was run in. All of those caps could be near end-of-life -- in which case I'm sure they'll restore the "magic" of the loudspeaker by emasculating the midrange and high frequency response. They may even be close to providing some much needed lubrication to the crossover boards.

[ka7niq]

Most of those you find will be polypropylene in oil. If made well they will have very low ESR. The best I have used were made by either GE or Aerovox. I used the GE ones in my crossover work as long as GE was building them.

Bob Crites

They have Aerovox Bob I think, or may be Sprague, NOS ones too. I have not actually placed my order yet, but it is stored in a shopping cart on their page. My kid took off with my Visa, and they dont take PayPal. I selected by weight, not brand or condition, hoping the old, used ones may be paper in oil like the Russian Paper in Oil being sold. I have read several articles about mechanical resonances in capacitors,and their effect on sound. Clarity Caps even has a white paper on this,and make a big deal about it.

[ka7niq]

I don't trust those people -- it looks like they're selling stuff.

Seriously though, they don't tell you anything about them except that they're used and have been pulled from equipment. They don't tell you what they are, how old they are, what kind of equipment they were pulled from, or the environmental condition the equipment was run in. All of those caps could be near end-of-life -- in which case I'm sure they'll restore the "magic" of the loudspeaker by emasculating the midrange and high frequency response. They may even be close to providing some much needed lubrication to the crossover boards.

Thanks for Pic Dean, now I see how they mount. I selected, but have not yet bought the used ones. They have NOS ones at the same price.

[Marvel]

Bob- have you tried any of the Genteq caps? They are around $5-$10 from Newark. They are probably made in China, but the parent company is Regal-Beloit, with their HQ in Beloit, WI. The polyprop. caps in their new oil are 2uF-120uF. I'm sure some HVAC vendors also carry them.

Bruce

[ka7niq]

Most of those you find will be polypropylene in oil. If made well they will have very low ESR. The best I have used were made by either GE or Aerovox. I used the GE ones in my crossover work as long as GE was building them.

Bob Crites

Here is the New Aerovox Bob http://www.surpluscenter.com/item.asp?item=22-1300&catname=electric I know you liked these type of capacitors.

[ka7niq]

Don't use there in any of my designs!

AL K.

You dont like motor run capacitors AL ? They have NOS ones. My brother Jamie is an A/C Contractor www.jamiesairconditioning.com AL, I am kind of hoping they sound good. It will be worth it in "shock value" for my brother to see the same kind of caps he uses in his line of work, on my crossover boards.

[BEC]

Most of those you find will be polypropylene in oil. If made well they will have very low ESR. The best I have used were made by either GE or Aerovox. I used the GE ones in my crossover work as long as GE was building them.

Bob Crites

They have Aerovox Bob I think, or may be Sprague, NOS ones too. I have not actually placed my order yet, but it is stored in a shopping cart on their page. My kid took off with my Visa, and they dont take PayPal. I selected by weight, not brand or condition, hoping the old, used ones may be paper in oil like the Russian Paper in Oil being sold. I have read several articles about mechanical resonances in capacitors,and their effect on sound. Clarity Caps even has a white paper on this,and make a big deal about it.

The reason the ones you picked out are heavier is because of higher working voltage, so they need more oil. That is what the oil is for, better cooling for the high power application these are used in. They are all likely polypropylene to keep ESR low. In the intended application for these, high ESR makes them perform like a grenade.

Bob

[BEC]

Bob- have you tried any of the Genteq caps? They are around $5-$10 from Newark. They are probably made in China, but the parent company is Regal-Beloit, with their HQ in Beloit, WI. The polyprop. caps in their new oil are 2uF-120uF. I'm sure some HVAC vendors also carry them.

Bruce

Bruce,

Can't remember if Genteq is a brand I tested or not. When GE sold their tooling for the motor run caps to some Chinese company, I hoped the quality of those would stay the same, but it did not. By the way, those are now branded Dayton and sold by Grainger. This is just plain wierd to me. They used the same tooling and materials and turned an excellent cap into a poor performer and increased the price. I probably need to order a few more of the Daytons to see if they are better now. Sometimes there is a learning curve for a company making a new product.

Bob

[ka7niq]

Most of those you find will be polypropylene in oil. If made well they will have very low ESR. The best I have used were made by either GE or Aerovox. I used the GE ones in my crossover work as long as GE was building them.

Bob Crites

They have Aerovox Bob I think, or may be Sprague, NOS ones too. I have not actually placed my order yet, but it is stored in a shopping cart on their page. My kid took off with my Visa, and they dont take PayPal. I selected by weight, not brand or condition, hoping the old, used ones may be paper in oil like the Russian Paper in Oil being sold. I have read several articles about mechanical resonances in capacitors,and their effect on sound. Clarity Caps even has a white paper on this,and make a big deal about it.

The reason the ones you picked out are heavier is because of higher working voltage, so they need more oil. That is what the oil is for, better cooling for the high power application these are used in. They are all likely polypropylene to keep ESR low. In the intended application for these, high ESR makes them perform like a grenade.

Bob

I figured the more oil, the better damping on mechanical vibrations ?

[BEC]

I am pretty sure that mechanical vibration was pretty low on the list of concerns for people who make these caps as long as those vibrations were not enough to cause an internal lead to break.

Bob

[jorjen]

Grainger used to carry GE but I think now they only sell Dayton and Proline. Alot more expensive though, just thought I would mention it.

[Marvel]

Can't remember if Genteq is a brand I tested or not. When GE sold their tooling for the motor run caps to some Chinese company, I hoped the quality of those would stay the same, but it did not. By the way, those are now branded Dayton and sold by Grainger. This is just plain wierd to me...

I just dug a little deeper on the Newark catalog site.

They list GE Caps by Regal-Beloit! I guess you might have tested some...

[ka7niq]

I am pretty sure that mechanical vibration was pretty low on the list of concerns for people who make these caps as long as those vibrations were not enough to cause an internal lead to break.

Bob

I am sure you are correct, The Oil and metal case are most likely there only to privide heat dissapation and mechanical strength from squirrels and other varmints chewing through the caps on an outside a/c unit. It is said that raccoons and squirrels just loved the taste of PCB's[:'(]

[Paul Hale]

The lighter ones may actually be best if they're in an aluminum can, as opposed to a steel can (heavier). Most of the GE motor runs I've come across were in aluminum cans, which may be good for a crossover that's anywhere near big magnets. Also I haven't had any GE caps that looked like they had been leaking. New GE's were relatively expensive motor runs, and may be among the best built. I think they sound pretty good, especially in tube amp power supplies. I've used 'em in Klipsch crossovers to good effect, too, but it just could be that they were simply newer and better caps than the old leaky originals they replaced. I've gotten most of my motor runs from local surplus stores. The advantage of seeing them first is to note whether they're used or new (appearance of the terminals), note the production date, and guess if they've been leaking by checking for any oily residue near the terminals. You can also hold them close to your ear and tap on them to guess at the fluid content, but of course you don't want anyone to see you listening to caps in this fashion.... Too bad most of these otherwise high quality cheap (from surplus) poly caps have steel connecting terminals (the GE's too), and are in steel cans. If you're into experimenting, the push-on terminals allow you to exchange caps without soldering.

[ka7niq]

I ordered enough of these motor run caps to re do my Electro Voice Sentry III's.

Order Number: I0155489

Ship To:
CHRIS



2 22-1161 2 MFD 660 VAC RUN CAPACITOR 3.98
2 22-1122 17.5 MFD 370 VAC RUN CAPACITOR 8.30
6 22-1107 30 MFD 330 VAC RUN CAPACITOR 29.34

Total $: 41.62
____________________________________________________________________________

Order Recap:
Total Product $: 41.62
Net Product$: 41.62
Shipping: 16.19
Sales Tax: 0.00
Insurance : 2.00
Grand Total: 59.81
____________________________________________________________________________

price for all these caps was very reasonable. The stock caps in the Sentry III's do not measure bad, after 36 years! They are right on the money! Have no way for ESR measure.

I replaced the stock caps with ERSE replacements, and they Sentry's sound like crap. No one has been able to figure out WHAT kind of caps the 6 - 30uf ones are, but they measure well, at lest for capacitance. I figured what the heck, lets try these motor run caps, can't hurt anything ? Plus, they look cool.

I have rigged the E/V Sentry III's for easy crossover rolling of capacitors, they shipped today! I am excited to try them, since exact stock type replacements did not do it for me.

[ka7niq]

The lighter ones may actually be best if they're in an aluminum can, as opposed to a steel can (heavier). Most of the GE motor runs I've come across were in aluminum cans, which may be good for a crossover that's anywhere near big magnets. Also I haven't had any GE caps that looked like they had been leaking. New GE's were relatively expensive motor runs, and may be among the best built. I think they sound pretty good, especially in tube amp power supplies. I've used 'em in Klipsch crossovers to good effect, too, but it just could be that they were simply newer and better caps than the old leaky originals they replaced. I've gotten most of my motor runs from local surplus stores. The advantage of seeing them first is to note whether they're used or new (appearance of the terminals), note the production date, and guess if they've been leaking by checking for any oily residue near the terminals. You can also hold them close to your ear and tap on them to guess at the fluid content, but of course you don't want anyone to see you listening to caps in this fashion.... Too bad most of these otherwise high quality cheap (from surplus) poly caps have steel connecting terminals (the GE's too), and are in steel cans. If you're into experimenting, the push-on terminals allow you to exchange caps without soldering.

Well Paul, my motor run caps arrived last week. I ordered all oval caps, but got 2 17.5 uf round ones! I complained, and they sent me out 2 replacements. The replacements are HUGE oval Aerovox Caps, and I do mean HUGE. They dwarf the 30uf Caps! Went down to Lowes, got some plastic conduit clamps touse to secure the monsters to the E/V Sentry III crossover board. I still have the Aerovox 17.5 Round Caps, so maybe I will experiment ? The 2uf Tweeter caps are GE Aluminums,and the 3 30uf Caps in each Sentry III crossover are Ronkens. I wish I had a schematic for the Sentry III crossover. It uses 3 30uf caps, wonder what ones are woofer roll off,and what one is midrange high pass ? It uses 2 of them in parallel on one circuit, and a single 30uf on another.

I would assume the two 30uf's are woofer dump caps ? I have 2 brand new high quality ERSE electrolytics in there right now, like to leave them in, it will be a lot easier then mounting 2 of these huge motor runs. Oh, the 3 - 30uf motor runs all have resistors soldered across the terminals, unlike the other caps I bought. I was told to just clip the resistors. I did shake the caps, and listen for Oil sloshing around, and the huge 17.5 uf Aerovox Caps sound like a millk shake !!! Lots of slushing going on !!! If indeed the 2 30uf Caps are in the woofer circuit of the Sentry 3's, then the remaining 30uf Cap must be for the bottom of the midrange crossover,and the 17.5 for the midrange roll off. But w/o a crossover schematic, I can only guess.

Crossover points in the E/V Sentry 3 are at 600 and 3.5k.