On 11 Feb 2007 06:08:19 -0800, "ASTONboy" wrote:

I have a Record Power (DML24X/C) lathe and in order to change the
speeds I have to open up the motor casing and change the position of
the belt. Is there any way to change this so that the speed can be
adjusted from the outside.

Three phase motors are usually less expensive per horsepower than single phase
or DC powered equivalents. In addition, some of the newer vfd's that utilize
the new generation of solid state power switching devices are also less
expensive as well. I think it is the more widespread use of three phase
commercially that creates more power control options being designed to compete
in that market due to it's size. A good selection of three phase motors I have
found is www.surpluscenter.com. There are a number of ebay sellers who sell
competitively priced, new electronic speed controllers for three phase, and
single phase ac, 'plus DC controllers as well, sometimes matched with an
appropriately sized motor.

Three phase power from the power company is Not a requirement to operate a vfd
three phase motor controller as vfd's are available that use single phase ac
input and provide three phase output to the motor.

Look for motors with a service factor ("SF" on the motor spec plate) that is
greater than 1.0, like 1.15, etc. This indicates how much the motor can
intermittently be driven beyond it's rated hp without risk of damage to the
motor. The higher the SF the longer and more reliable the unit should be
generally, usually weighing more due to more robust construction.

hope this helps someone out there...regards, Joe

PS: email me with any questions as I am sometimes not on the ng's on a regular
basis....check mail at least every couple of days though.