Pressure washer capacitor replacement
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From: PeterD on 28 Sep 2009 19:03 On Mon, 28 Sep 2009 22:29:28 +0000 (UTC), Foo <moo(a)not.here> wrote: > >I agree that it would be the best solution, and as Meat Plow suggested >above, using capacitors of different values in parallel cannot be good. > >However, finding a good replacement part won't be easy (I will have to go >out or something equally complicated) and probably a bit expensive. > >In the meantime, I was thinking about an alternate solution to avoid >damaging my capacitors: since the motor seems able to run without them, >what if I disconnect them after it's started? > >Alternatively, I'd like to know what would happen if I use less capacitance, >using 2x13uF or 14uF only. Will it be a power/performance problem or will >something get damaged? Disconnecting might work, they are for starting probably. But if it is capacitor run then it may be a bad idea. You may find that 2x13 works OK...
From: David Lesher on 28 Sep 2009 22:21 PeterD <peter2(a)hipson.net> writes: >Disconnecting might work, they are for starting probably. But if it is >capacitor run then it may be a bad idea. If they were starting-only, they'd not be getting hot while running. -- A host is a host from coast to coast.................wb8foz(a)nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
From: Foo on 29 Sep 2009 04:13 On 2009-09-28, Sjouke Burry <burrynulnulfour(a)ppllaanneett.nnll> wrote: > webpa(a)aol.com wrote: >> On Sep 28, 5:29 pm, Foo <m...(a)not.here> wrote: >> >> It is likely the capacitor does nothing except participate in >> generating a pseudo-rotating stator field during starting. Once the >> motor is running, it does nothing at all. > > The cap produces a pseudo-rotating stator field, and is dragging the > rotor around, even after startup. > If you leave the cap out after starting, the bulk of the torque is lost. > That is,for the motors designed with a permanent cap. I'll try disconnecting them or using a single, smaller cap. If the resulting torque is not enough, I'll buy something equivalent to the original. Thanks everyone. -- Foo
From: Foo on 29 Sep 2009 14:11 On 2009-09-29, Meat Plow <meat(a)petitmorte.net> wrote: > On Mon, 28 Sep 2009 22:29:28 +0000 (UTC), Foo <moo(a)not.here>wrote: > >>In the meantime, I was thinking about an alternate solution to avoid >>damaging my capacitors: since the motor seems able to run without them, >>what if I disconnect them after it's started? >> >>Alternatively, I'd like to know what would happen if I use less capacitance, >>using 2x13uF or 14uF only. Will it be a power/performance problem or will >>something get damaged? > > > Do yourself a favor and try to find a replacement of value within the > rated specs. The motor needs that cap to start and run if it is not > designed to disconnect after startup. > > You have to weigh the cost of a replacement cap against: > > 1. Risk of electrocution (priority) > 2. Risk of motor damage > 3. Do I really need a pressure washer > 4. What would it cost to replace the whole thing. > > Caps are generally available as either exact factory replacement > (recommended) or OEM if you do a little homework. Yes, of course. I seldom use this pressure washer and don't have the right capacitor at hand. To be honest, it was more a "what if?" question to try to use what I have here and understand what could go wrong. Thanks. -- Foo
From: PlainBill47 on 29 Sep 2009 14:56
On Mon, 28 Sep 2009 22:29:28 +0000 (UTC), Foo <moo(a)not.here> wrote: >On 2009-09-28, PlainBill47(a)yahoo.com <PlainBill47(a)yahoo.com> wrote: >> On Mon, 28 Sep 2009 15:06:53 +0000 (UTC), Foo <moo(a)not.here> wrote: >> >>>A few years ago, the motor capacitor from my pressure washer exploded, >>>it was a large 50uF non-polarized, plastic-cased run capacitor for >>>a 230V, 2750W motor. Interestingly, it didn't stop the motor right away >>>but it couldn't restart when shut down. >>> >>>Its case read ILCEA K 45 5000 50uF +/- 5%b 450V HPFPU. >>> >>>Because the device was over ten years old, I didn't bother to repair >>>it but kept it anyway, until a few months ago when someone gave me four >>>large alumin(i)um-cased caps: 13uF 13uF 14uF and 10uF (non polarized, >>>450V max or so, all from Bosch). >>> >>>So I decided to wire them in parallel in place of the old one, and it >>>worked as before even under maximum load. >>> >>>After 10 minutes of use, I stopped the motor to make sure the capacitors >>>were not overheating and found that the two 13uF caps were hotter than >>>the others (still able to touch them with my bare hand, but the two others >>>were still at room temperature). >>> >>>Does it mean that only those two actually work, do you think it's safe >>>to continue operating the device, or will they keep heating up until they >>>meet their fate too? >>> >>>Thanks. >> It is likely that only the two that are heating up actually work. If >> you wish to use the pressure washer I would suggest buying the correct >> part. Cobbling together several capacitors for a piece of equipment >> that is handling water at high pressure doesn't seem safe. > >I agree that it would be the best solution, and as Meat Plow suggested >above, using capacitors of different values in parallel cannot be good. > >However, finding a good replacement part won't be easy (I will have to go >out or something equally complicated) and probably a bit expensive. > >In the meantime, I was thinking about an alternate solution to avoid >damaging my capacitors: since the motor seems able to run without them, >what if I disconnect them after it's started? > >Alternatively, I'd like to know what would happen if I use less capacitance, >using 2x13uF or 14uF only. Will it be a power/performance problem or will >something get damaged? I'm not sure how run capacitors are wired into a motor like this. A few years back my 'high efficiency' pool pump started overheating. The thermal protector would shut it down. Investigation showed the run capacitor had failed. Replacing it solved the problem. IF that is the only function of a run capacitor you could probably use the pressure washer for short periods without the capacitor. Inevitably it will lead to other problems. As far as being expensive, a quick search on eBay finds a store selling a 50�F 440Volt capacitor for $7.00. PlainBill |