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-   -   oil-filled electric motors, topping up? (https://www.diybanter.com/uk-diy/355240-oil-filled-electric-motors-topping-up.html)

Jules Richardson[_2_] April 15th 13 04:01 PM

oil-filled electric motors, topping up?
 


I've got an electric sewer pump which uses an oil-filled motor - the
lower seal had a tiny leak which I fixed, but it could use a little
topping up before I use it in anger (the upper bearing's *just*
protruding above the oil surface, so it doesn't need much to cover it
again).

Now, I think that the correct stuff is termed dielectric oil (which I've
been unable to find locally) - but that this *might* be the same as
transformer oil? (I've not seen the latter locally either, but at least
it lets me broaden my search!)

I also saw TNP mention recently that big transformers are filled with
mineral oil; is that true? Mineral oil I can certainly get (and indeed I
have a bottle somewhere) - unless of course not all mineral oils are
created equal, and the consumer-grade stuff is a completely different
animal :-)

cheers

Jules

harry April 15th 13 05:01 PM

oil-filled electric motors, topping up?
 
On Apr 15, 3:01*pm, Jules Richardson
wrote:
I've got an electric sewer pump which uses an oil-filled motor - the
lower seal had a tiny leak which I fixed, but it could use a little
topping up before I use it in anger (the upper bearing's *just*
protruding above the oil surface, so it doesn't need much to cover it
again).

Now, I think that the correct stuff is termed dielectric oil (which I've
been unable to find locally) - but that this *might* be the same as
transformer oil? (I've not seen the latter locally either, but at least
it lets me broaden my search!)

I also saw TNP mention recently that big transformers are filled with
mineral oil; is that true? Mineral oil I can certainly get (and indeed I
have a bottle somewhere) - unless of course not all mineral oils are
created equal, and the consumer-grade stuff is a completely different
animal :-)

cheers

Jules


About twenty years ago many were filled with PCB, a carcinogen.
You can't use mineral oil but transformer oil should be OK.
The oil has to be compatible with the insulation on the windings.

The oil is there primarily to cool the windings, it carries the heat
to the water being pumped.

The Natural Philosopher[_2_] April 15th 13 07:36 PM

oil-filled electric motors, topping up?
 
On 15/04/13 16:01, harry wrote:
On Apr 15, 3:01 pm, Jules Richardson
wrote:
I've got an electric sewer pump which uses an oil-filled motor - the
lower seal had a tiny leak which I fixed, but it could use a little
topping up before I use it in anger (the upper bearing's *just*
protruding above the oil surface, so it doesn't need much to cover it
again).

Now, I think that the correct stuff is termed dielectric oil (which I've
been unable to find locally) - but that this *might* be the same as
transformer oil? (I've not seen the latter locally either, but at least
it lets me broaden my search!)

I also saw TNP mention recently that big transformers are filled with
mineral oil; is that true? Mineral oil I can certainly get (and indeed I
have a bottle somewhere) - unless of course not all mineral oils are
created equal, and the consumer-grade stuff is a completely different
animal :-)

cheers

Jules

About twenty years ago many were filled with PCB, a carcinogen.
You can't use mineral oil but transformer oil should be OK.


'mineral oil' is a very broad category. AFAIK transformer oil IS a
mineral oil, but only one of many.

But I agree, transforner oil is a safe bet.

http://en.wikipedia.org/wiki/Transformer_oil


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.


Newshound April 15th 13 09:46 PM

oil-filled electric motors, topping up?
 
On 15/04/2013 18:36, The Natural Philosopher wrote:
On 15/04/13 16:01, harry wrote:
On Apr 15, 3:01 pm, Jules Richardson
wrote:
I've got an electric sewer pump which uses an oil-filled motor - the
lower seal had a tiny leak which I fixed, but it could use a little
topping up before I use it in anger (the upper bearing's *just*
protruding above the oil surface, so it doesn't need much to cover it
again).

Now, I think that the correct stuff is termed dielectric oil (which I've
been unable to find locally) - but that this *might* be the same as
transformer oil? (I've not seen the latter locally either, but at least
it lets me broaden my search!)

I also saw TNP mention recently that big transformers are filled with
mineral oil; is that true? Mineral oil I can certainly get (and indeed I
have a bottle somewhere) - unless of course not all mineral oils are
created equal, and the consumer-grade stuff is a completely different
animal :-)

cheers

Jules

About twenty years ago many were filled with PCB, a carcinogen.
You can't use mineral oil but transformer oil should be OK.


'mineral oil' is a very broad category. AFAIK transformer oil IS a
mineral oil, but only one of many.

But I agree, transforner oil is a safe bet.

http://en.wikipedia.org/wiki/Transformer_oil


Not sure how easy it will be to buy in small quantities though.

Just to clarify, mineral oil just means oil which has been refined from
crude oil. Just carbon and hydrogen plus whatever impurities have been
left in (typically organic sulphur compounds, perhaps some fatty acids).

What you need in your case is something with broadly the same viscosity
as the existing oil. Not too many additives, so I wouldn't use motor
oil. The most pure mineral oil which is readily available in small
quantities is Liquid Paraffin BP from any chemist. Baby oil is nearly as
pure, but it has an added smell. (Baby oil is thinner than liquid
paraffin). If you are just topping up existing oil (say, less than 10%)
I'd probably go with liquid paraffin, but I think baby oil would work
too. (It works on sewing machines).

I expect it is a brushless motor. The electric fields are likely to be
trivial compared to conditions in a high voltage transformer, so the
selective formulations found in transformer oils give no benefit.



[email protected] April 16th 13 02:48 AM

oil-filled electric motors, topping up?
 
On Monday, April 15, 2013 3:01:23 PM UTC+1, Jules Richardson wrote:
I've got an electric sewer pump which uses an oil-filled motor - the
lower seal had a tiny leak which I fixed, but it could use a little
topping up before I use it in anger (the upper bearing's *just*
protruding above the oil surface, so it doesn't need much to cover it
again).


Tansformer oil often describes a toxic carcinogenic organ killing liquid, so I'm wary of any such stuff. A thin mineral oil with no additives should work nicely, whatever the original is. The easiest way to get that is to heat up some baby oil to drive the whiff off.


NT

Grimly Curmudgeon[_3_] April 18th 13 08:41 PM

oil-filled electric motors, topping up?
 
On Mon, 15 Apr 2013 20:46:44 +0100, newshound
wrote:

The most pure mineral oil which is readily available in small
quantities is Liquid Paraffin BP from any chemist. Baby oil is nearly as
pure, but it has an added smell.


Hellfire. Raises a question of just how safe baby oil is. I assumed it
was palm oil or similar.

Newshound April 18th 13 10:01 PM

oil-filled electric motors, topping up?
 
On 18/04/2013 19:41, Grimly Curmudgeon wrote:
On Mon, 15 Apr 2013 20:46:44 +0100, newshound
wrote:

The most pure mineral oil which is readily available in small
quantities is Liquid Paraffin BP from any chemist. Baby oil is nearly as
pure, but it has an added smell.


Hellfire. Raises a question of just how safe baby oil is. I assumed it
was palm oil or similar.


OK I guess some baby oils may be vegetable based, but I'm sure that some
used to be mineral. But "liquid paraffin BP" is considered safe to drink
so I'd expect it to be pure enough not to cause skin reactions even in
the most sensitive of persons. Remember that paraffins (in the proper
chemical sense) are very unreactive, whether as oil, paraffin wax, or
polyethylene and polypropylene (except when set alight).



polygonum April 18th 13 10:22 PM

oil-filled electric motors, topping up?
 
On 18/04/2013 21:01, newshound wrote:
On 18/04/2013 19:41, Grimly Curmudgeon wrote:
On Mon, 15 Apr 2013 20:46:44 +0100, newshound
wrote:

The most pure mineral oil which is readily available in small
quantities is Liquid Paraffin BP from any chemist. Baby oil is nearly as
pure, but it has an added smell.


Hellfire. Raises a question of just how safe baby oil is. I assumed it
was palm oil or similar.


OK I guess some baby oils may be vegetable based, but I'm sure that some
used to be mineral. But "liquid paraffin BP" is considered safe to drink
so I'd expect it to be pure enough not to cause skin reactions even in
the most sensitive of persons. Remember that paraffins (in the proper
chemical sense) are very unreactive, whether as oil, paraffin wax, or
polyethylene and polypropylene (except when set alight).


Though they did stop using it on things like dried vine fruits some
years ago. Can't remember why.

--
Rod

Phil Wieland April 19th 13 05:11 PM

oil-filled electric motors, topping up?
 
On 18/04/13 21:01, newshound wrote:
On 18/04/2013 19:41, Grimly Curmudgeon wrote:
On Mon, 15 Apr 2013 20:46:44 +0100, newshound
wrote:

The most pure mineral oil which is readily available in small
quantities is Liquid Paraffin BP from any chemist. Baby oil is nearly as
pure, but it has an added smell.


Hellfire. Raises a question of just how safe baby oil is. I assumed it
was palm oil or similar.


OK I guess some baby oils may be vegetable based, but I'm sure that some
used to be mineral. But "liquid paraffin BP" is considered safe to drink
so I'd expect it to be pure enough not to cause skin reactions even in
the most sensitive of persons.

....

Just to be clear, that's British Pharmacopoeia rather than British
Petroleum, who might well also sell Paraffin.

(-;

--
Phil
Liverpool, UK


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