gear box selection

[arjun.b]

Hi,

I have a elec generating unit. The shaft has a rpm of 15000. Need to reduce to 250-300rpm i.e. bring it down to generating elec at 50Hz. Could somebody suggest which gearbox is suitable for this application to reduce from high to low rpm. Also suggest which type of coupling has to be used between the shaft and the generator.

Thank you...

[brewnog]

15000rpm or 1500rpm?

How big is your generator? Most commercial generators run at 1,500rpm, not sure why you're after 250-300rpm.

[Mech_Engineer]

The gearbox's reduction is only one requirement that you will need to specify a gearbox for your application. The most important things you haven't mentioned yet is how much power will this gearbox be transmitting, and in a related vein how much torque on the input and output shafts?

[arjun.b]

Power generated: 25KW
Input power: 45 hp (33.6 kW)
axes: parallel
low speed shaft: 3000rpm
high speed shaft: 15,700 rpm
center distance: 3.125-inches (79.375 mm)
spur gear or low helix angle (whichever is more efficient, less expensive and low noise) ?
AGMA class 9, 10 or 11 (depending on cost)
life: 60,000 hrs

[Mech_Engineer]

Take a look at GlobalSpec.com's Gearboxes and Gearheads search. They have a lot of different stuff in there, and you can narrow your search one parameter at a time (for example, reduction and power throughput). It sounds like you could have some trouble based on the input shaft speed (15000 rpm) but who knows you might find something...

http://www.globalspec.com/SpecSearch/Suppliers/Motion_Controls/Drive_Components/Gearboxes_Gearheads

If the input shaft speed does become a problem, you might consider stacking a pair of gearboxes, one reducing from 15000 rpm to around 3000, and then another gearbox that reduces to your final shaft speed.