# Bosch touts its compact and flexible electric motor



## CHARGED EVs Magazine (Nov 14, 2011)

Bosch touts its compact and flexible electric motor... Newswire >


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## PStechPaul (May 1, 2012)

I found another article about this motor:
http://www.edn.com/electronics-products/other/4420649/E-car-motor-fits-into-school-backpack

Here is the press release:
http://www.bosch-presse.de/presseforum/details.htm?txtID=6226&tk_id=108

One major drawback to this motor for use as direct drive to wheels is that it delivers its maximum 80 kW at 12,800 RPM. Its 200 N-m torque is impressive, but for a 24" diameter tire at 50 MPH it spins at 707 RPM and 200 N-m wheel torque will push a 1000 kg vehicle up a 4% slope. It really needs a 10:1 reduction drive to be really useful. If you put one of these motors on all four wheels, it becomes pretty awesome, but still it is not well matched for speed. At its maximum RPM the vehicle would move at 905 MPH! 

Apparently the 200 N-m torque does not apply at 12,800 RPM because that would be 270 kW. So for that torque at 707 RPM it is 15 kw (20 HP), and 80 kW at 12,800 RPM is 60 N-m.


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## Ellrot (May 17, 2010)

Good points. Would a 5:1 reduction box would give a max rpm of 6400 if coupled with a standard transmission?


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## PStechPaul (May 1, 2012)

6400 RPM would be a 2:1 reduction. If you already have a standard transmission and differential you should be able to use the motor as-is for good results. The rear axle ratio is usually about 3:1 and the transmission may have a range of 3:1 to 1:1 and possibly overdrive. With a "redline" of 12,800 you could hit 80-100 MPH in first gear and 240-300 MPH in 3rd or 4th!


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## Ellrot (May 17, 2010)

ah ofc, sorry I was getting my fractions and decimals mixed up!


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