Pump Capacitor

[Biguns]

Friends Grundfos 15-45 x18 pump giving problems.I know it is the capacitor that has failed. The pump is otherwise fine. Try as I may I can not find a replacement capacitor on the net, Maplins and Screwfix dont do them. Anyone got any ideas
The failed one is a :- Pye MK. 2.5uf. 350 volt. 50Hz

Maplin's do a one which is 400 volt will that one work?

Or are we now expected to pay £60 for a new pump instead of £3 or £4 for a part

 

[Burnerman]

No probs using that one mate - it could be slightly larger, if that matters.
John

 

[nickso]

it wouldn't need to be in the housing if it won't fit though.

often wondered why the cheapskates a BG towers have not sourced new capacitors for us to use.

 

[Biguns]

Cheers John.
If it is physicaly too big to go inside the the pump electrical conection box I will secure it on the outside.

 

[Bunnyman]

We get our 3 farad ones from rs components corby

Untitled

• Bunnyman
• 26 Mar 2010
• 499

 

[MrGassafe]

We get our 3 farad ones from rs components corby

Untitled

• Bunnyman
• 26 Mar 2010
• 499

THREE FARADS

 

[Bunnyman]

U know what I mean lol! 3uf

 

[SimonH2]

often wondered why the cheapskates a BG towers have not sourced new capacitors for us to use.

Because that would mean carrying more spares, and not being able to sell a whole pump

 

[Andygasman2010]

often wondered why the cheapskates a BG towers have not sourced new capacitors for us to use.

Because that would mean carrying more spares, and not being able to sell a whole pump

They don't sell pumps!

It'd actually make sense for them to change the capacitors only, wonder why they don't!

 

[ChrisR]

snugib - haven't you got a dud pump you can pinch one from?

 

[Agile]

Warning with a 400v cap !

Make sure that its one designed for AC !

Tony

 

[matt1e]

Warning with a 400v cap !

Make sure that its one designed for AC !

Tony

A 400V DC rated capacitor will be well within spec for 230V AC

I think I can see where you are coming from tony, but
230vac (RMS) = 325V peak to peak (hence the 350v rating of the original)

Matt

 

[mikeyd]

A 400V DC rated capacitor will be well within spec for 230V AC
Matt

Some types (electrolytic, tantalum etc.) are polarised so only work on DC
and must be connected the right way round.

 

[matt1e]

A 400V DC rated capacitor will be well within spec for 230V AC
Matt

Some types (electrolytic, tantalum etc.) are polarised so only work on DC
and must be connected the right way round.

I Know, but we are talking about a single phase ac motor cap here so irrelevant, though granted the op should be fitting the correct type of cap

Matt

 

[Agile]

I have to disagree with you there Matt.

Its not the voltage thats relevant but the current through it.

Applying AC to a capacitor creates a current which will generate heat and in relation to motor or PFC caps requires a power rating which will accommodate the considerable heat generated.

Smoothing caps are rated for the AC current through them as well as the DC maximum voltage.

Furthermore with mains voltages subject to significant surges and spikes a safety factor for voltage is usually at least 1.5 times the expected nominal voltage.

Tony