Re: (ET) Kid car idea

["John de Rivaz" <John deRivaz com>]

> I was checking in my shop and I have a 50 VDC nominal
> motor (that came out of a 9-track computer tape drive made by DEC)

I would rather doubt it. The power required to haul a kid about in a toy 
car
is somewhat more than move tape. However there is a rule of thumb mentioned
on this list or possibly a UK one which said that your electric motor can 
be
1/4 the horsepower of a gas engine used in a similar application. This is
because the electric motor is capable of brief overloads, whereas a gas
motor just stops. Therefore the gas HP has to be the peak load expected. If
you know the sort of HP a gas engine would be, then divide by 4 and you get
the electric HP needed. I HP = 746 watts. For a DC motor, the power in 
watts
= emf (volts) x current (amps) x efficiency. Efficiency is high, about 90%
(which would be 0.9 in the suggested calculation).

--
Sincerely, John de Rivaz:      http://www.deRivaz.com :
http://www.AlecHarleyReeves.com
http://www.longevity-report.com : http://www.autopsychoice.com :
http://www.cryonics-europe.org
http://www.porthtowan.com

----- Original Message -----
From: "SolidTech" <SolidTech qwest net>
To: "'Elec-Trak'" <elec-trak cosmos phy tufts edu>
Sent: 25 June 2002 18:18
Subject: (ET) Kid car idea


> All,
>   Hoping for some thoughts on feasibility (and refinement) of the idea of
> making a "better than retail" kid car.  I know there's the plastic
electric
> vehicles you can buy at your local toy/department store.  They always 
> seem
a
> bit pricy for the mostly plastic thing they are.  So...  I was
contemplating
> a simple go-cart style vehicle with 1/2/3 batteries, a controller, and an
> appropriate motor.  I was checking in my shop and I have a 50 VDC nominal
> motor (that came out of a 9-track computer tape drive made by DEC) and I
see
> there's various controllers on eBay.  Questions: Is that electric motor
> (Ametek brand) even appropriate for the task?  What would be a reasonable
> number/size of batteries?  What would be appropriate for a controller?
>
> thoughts?
> - - joe
>
> Joseph Rock
> E-15 & MagnaTrac Hydro 5000 in Colorado
>
>