Is there any technology/method/parts available for a fast moving hoist
on a 40 metre track to draw power from a brush (or brushless) contact
without any
sparks? Its 24V 15amp. maximum. |
Clarification of Question by
kamal_61-ga
on
31 Aug 2005 21:57 PDT
It is 24 Volts. DC. As the "hoist" should work in a condition averse
to sparks and it cannot have (slackened) feed cables/wire attached to
it, I'm depending on this kind of brush/contact. Let me clarify again,
the technology I'm looking here is not for the Hoist but the
"sparks"less brush/contact.
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Request for Question Clarification by
hedgie-ga
on
08 Sep 2005 23:49 PDT
Kamal, that question still is not clear.
Are you talking about the supply of power to the electric motor
which is on a moving carriage. collectors such as
( pantographs, bow collectors, or trolley poles)
or about the sparks in the motor itself.
In the first case, would supply by a cable do? If not, why not>
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Clarification of Question by
kamal_61-ga
on
09 Sep 2005 03:39 PDT
Hi hedgie
Yes. I meant supply of power to the electric motor which is on a
moving carriage. Since the track may run in an inclined angle (slope),
and the said assembly may be used in a public place and not in a
industry environment, I feel supply cable is cumbersome and not safe.
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Kamal
answer is YES, there is such a technology, but it may not be
efficient and practical
for your application. It depends on power (i.e. Watts) rather on
Voltage and on the cost
and conditions (indoor outdoor). The idea is to supply the high
frequency power using induction.
It is used today to recharge small battery operated appliances, such
as dental brushes.
It can be scaled up do deliver power to run an electric motors. Full
engineering analysis
would be required to estimate the cost and efficiency.
Alternative to the this inefficient method are not always slacking
supply cables. Consider the
CABLE WINDER, which can be automatized to provide required length of the cable:
http://www.airport-technology.com/contractors/groundequipment/manfred/
http://www.drouaire.com/es/uk/bobicab2.htm
Similar solution is Festoon system which eliminates mobile collectors
which will prevent sparks,
small electrical arcs, and loss of energy.
http://www.keepitmoving.com/festoon.html
Other solution would be to provide power mechanically, by having one
or more or more mechanical cables
along the track. They do not pull the carriage (as in the case of
cable car) but rotate a wheel on the carriage
which is connected to an electric power generator.
Finally, variant on the first case, one can experiment with low
voltage, high frequency supply by
conductor rails and slip rings:
http://www.sonichindustrial.com/crane/wam.html |
Request for Answer Clarification by
kamal_61-ga
on
12 Sep 2005 09:26 PDT
Hi Hedgie
Thanks. It was a great help. Pardon pressing for more. The solution I
need is not for a heavy industry. Infact the BOX on a track/rail will
be 6"x4"x3" maximum and the weight that may be attached to it will be
of 3.5 kilos max. Since the whole assembly may be erected near
combustable materials ( like thin-sheets of paper) I'm worried about
safety. (12/24 volt. 15 amps. max). Moreover aesthetics is an
important issue.
I've a question. If either one of the contacts is made of semi-solid
like mercury will there be sparks? Imagine we design a high-tensile
non-conducting track/rail, embedded with live copper-wire carrying the
required power ( or a embedded thin tube filled with mercury ). And
the motor pick-up is actually a spot of mercury filled in a small
plastic enclosure, ( or a copper wire pick-up, incase the thin tube
filled with mercury ), can we acheive what I want?
(btw, im not a pro, so pardon my termnology)
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Clarification of Answer by
hedgie-ga
on
12 Sep 2005 14:48 PDT
Hi again Kamal
I only now notice your related question. It is always useful to make a reference
to any related material. Sketches can be uploaded to free site and pointed to ...
I do not see how the mercury spot and mercury wire would work - but I am pretty
sure you do not want to play with mercury:
Elemental, liquid mercury is slightly toxic, while its vapor,
compounds and salts are highly
toxic and have been implicated as causing brain and liver damage when
ingested, inhaled or contacted.
http://www.rednova.com/education/reference_library/?article_id=413
In particular, there must not be any open surface. Any conductive
contact, I can imagine implies open surface.
So, answer to that idea is NO.
Mercury is a bioaccumulative toxin that is easily absorbed through the
skin, respiratory and gastrointestinal tissues. Minamata disease is a
form of mercury poisoning. Mercury attacks the central nervous system
and endocrine system and adversely affects the mouth, gums, and
teeth...
http://www.idph.state.il.us/envhealth/factsheets/mercuryhlthprof.htm
http://www.epa.gov/region09/cross_pr/childhealth/mercury-nevada04.htm
Then we need to differentiate between combustible material and an
explosive environment. Electric motor itself can spark and cause explosion
in atmosphere where fuel vapors present, unless safety rules are followed.
http://www.engineeringtalk.com/news/fwo/fwo104.html
http://www.engineeringtalk.com/news/bal/bal112.html
http://www.baldor.com/products/product.asp?product=AC+Motors&family=Explosion+Proof%7Cvw_ACMotors_ExplosionProof
You need to follow the standards for your type of hazardous
environment and area( country).
http://www.teco.com.sg/2explo.htm
Please, do re-read the disclaimers (below) and be aware that local
inspection and may be
measurement may be required. Sparks can be generated even without
electricity (on impact).
The question then is HOW. Since your power need is modest (<300W) The
practical option is
high frequency transmission used e.g. in this consumer product:
http://www.boots.com/images/product/1002943/ehero.jpg
which I mentioned previously.
Power is transmitted across thin layer of plastics. There are no
sparks. You may have to take
one apart. There is more info under search terms:
SEARCH TERMS: Telsa coil, electrical impedance, high frequency
electric power transmission ..
It is not simple, and some people have (unfounded) fear of being near
high frequency fields.
Hedgie
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Clarification of Answer by
hedgie-ga
on
13 Sep 2005 00:23 PDT
Another possibility is LIM -
It does not fit exactly your question
of 'suplying power to conventional motor' but suggests an alternative solution
by using an unconventional motor. Physical principle is same : electric induction.
basic idea is here:
http://campus.umr.edu/physics/alab/limwebpage/LIM_files/frame.htm
example of use
http://www.memagazine.org/backissues/february2000/features/birds/birds.html
products for small scale use
http://www.h2wtech.com/linindmotor.htm
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Clarification of Answer by
hedgie-ga
on
13 Sep 2005 23:23 PDT
Thanks for the rating.
One more possibility - may be too original - but may be useful:
Use two carriages on the track -
both carry a motor+acumulator (=recharchable battery)
one carriage working, the other sits on one end and charging
They swap roles when one acumulator is empty
or (variant on the above) uses only one motor:
track carries three movable parts : subcarriage with motor
which can attach to a subcarriage with front or rear (or both) batteries.
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