Re: [CAD_CAM_EDM_DRO] Digest Number 1710
Posted by
Ronald Anderson
on 2001-10-18 07:19:14 UTC
VFD's
Variable Frequency Drives
I have been using them for the past 6 years on my Lathe and Mill.
The lathe has a 7 HP motor (3 phase) and had 60 amp fuses in the back
for start up with a contactor(relay).
With the VFD in place and a 3 second ramp up the machine will only
pull about 10 amps on the single phase input (amp meter is wired in
permanently). The lathe is large with a D1-8 spindle.
Any large motor being used as a converter will draw large amounts of
current on start up, many times its rating in HP for continous use.
Thus I never ran this lathe with the normal contactors, it was
immediately retrofitted with a VFD.
If you watch your cutting speeds and feeds you can limit the actual
amount of power being drawn by the motor through the VFD. A large
10-15 horsepower motor will only draw an equivalent power level if you
load it up through deep, heavy cuts. Thus it is still possible to run
a large motor with a smaller VFD. One can always add addtional caps to
the DC buss to limit the voltage variations.
On Ebay do a search for VFD's or Variable Frequency Dives, as there is
a guy in Canada who has been buying VFD's from Mitsubishi of America,
and selling them for cheap, all brand new. Look Up Mitsubishi too.
I bought a small 3 hp Mitsubishi version for about 300 dollars. My
other VFD's are all Baldor, they too are on the WEB and you can find a
local dealer through them.
Invest in a good VFD and you will not be sorry. If you have a large
shop with multiple pieces of equipment you could run all with one, by
selecting which motor gets hooked to the VFD and using a remote
control Pendent to control that machine motor via the VFD.
Today my next mill hits the floor and it will get a VFD too.
Ron
Variable Frequency Drives
I have been using them for the past 6 years on my Lathe and Mill.
The lathe has a 7 HP motor (3 phase) and had 60 amp fuses in the back
for start up with a contactor(relay).
With the VFD in place and a 3 second ramp up the machine will only
pull about 10 amps on the single phase input (amp meter is wired in
permanently). The lathe is large with a D1-8 spindle.
Any large motor being used as a converter will draw large amounts of
current on start up, many times its rating in HP for continous use.
Thus I never ran this lathe with the normal contactors, it was
immediately retrofitted with a VFD.
If you watch your cutting speeds and feeds you can limit the actual
amount of power being drawn by the motor through the VFD. A large
10-15 horsepower motor will only draw an equivalent power level if you
load it up through deep, heavy cuts. Thus it is still possible to run
a large motor with a smaller VFD. One can always add addtional caps to
the DC buss to limit the voltage variations.
On Ebay do a search for VFD's or Variable Frequency Dives, as there is
a guy in Canada who has been buying VFD's from Mitsubishi of America,
and selling them for cheap, all brand new. Look Up Mitsubishi too.
I bought a small 3 hp Mitsubishi version for about 300 dollars. My
other VFD's are all Baldor, they too are on the WEB and you can find a
local dealer through them.
Invest in a good VFD and you will not be sorry. If you have a large
shop with multiple pieces of equipment you could run all with one, by
selecting which motor gets hooked to the VFD and using a remote
control Pendent to control that machine motor via the VFD.
Today my next mill hits the floor and it will get a VFD too.
Ron