.... I think most 1 hp motors can run fine on 110, but for 1.5 hp, it will run far better with the 220. I have turned on the Jet 1642 with the 1.5 hp motor, and 110 volt. It is rather weak. It is not an issue of tighter belt or higher rpm, it just doesn't have much power.
This is comparing apples and oranges. The Jet 240 volt 1642 is 2 HP. Besides when you toss a VFD into the mix it becomes impossible to make a subjective comparison of motors because what you see is mainly how the VFD is designed to control the motor. I certainly support your observation that the 1.5 HP Jet is a 90 pound weakling, but it isn't because of the voltage. The VFD that Jet has used might not be the bottom of the heap, but it certainly isn't far from the bottom with respect to performance capability. When it comes to VFD performance, the operating voltage certainly does matter, but that is the VFD and not the motor.
I had one belt sander that had a 1 hp motor, and my jointer and drum sander both had 1.5 hp motors. I had them rewired to 220 volt. I didn't notice a lot of improvement on the belt sander, but big improvement on the other two tools. It could have been the power of suggestion, and I haven't turned on the Jet with the 220 volt motor, or the DVR with a 220 volt motor, so can't compare them with actual experience. I do know there is a huge difference in the actual motors, kind of like the difference in the 3/4 hp motor on my old Woodcraft blue no name grinder and my Baldor 3/4 hp grinder. The power difference is comparable to the weight difference, which is almost 2 to 1 in favor of the Baldor.
So Bill, what about my interpretation doesn't make sense. No offence taken at all, just curious.....
robo hippy
I didn't intend to imply that your interpretation didn't make sense, but that you conclusions based on your experience was incorrect. It might well appear logical to a reasonable person, but there can be other factors not accounted for that are the reason for what you believe. James mentions a couple of them. Another example would be comparing a 1.5 HP motor with a VFD operating on 120 volts on one machine to another fixed speed machine with a 1.5 HP single phase induction motor operating on 240 volts and having stepped cone pulleys to control the output speed. Also, saying that a motor ran "better" after rewiring might need a "better" description of what "better" means, if you know what I mean.
Also, never underestimate the power of suggestion -- it is often equivalent to one or two horsepower.
Most dual voltage motors will start quicker on the higher voltage. There will also be less voltage drop that can make a difference on long circuits. So I would agree with your observation that there is an improvement (in getting up to speed).
As James said, quicker start up is one thing that you can see on some single phase induction motors. That is because the same start winding configuration is used for either operating voltage. However, it would be worth pointing out that has nothing to do with motor performance once it is up and running. If it takes a motor 0.15 seconds to get up to speed when running on 120 volts, then it might take 0.09 seconds when running on 240 volts. Once the motor speed reaches roughly 2/3 of operating speed, the centrifugal switch kicks the start winding and start capacitor out of the circuit until the next time that the motor is started from a full stop. So, the faster startup is only good for warm fuzzies. It can't do anything to improve power output from the motor.
James mentioned voltage drop on long wiring runs, but really that is a red herring except in rare instances (it's rare if it happens to other people, but not to you.
). Most woodturners worry that their situation is one of those rare instances. I suppose that we all need to have something to worry about, but I like to worry about bigger things like whether the universe will continue expanding or will reverse and collapse into another "Big Bang". I would like to stick around to find out which way things go. I worry that I won't be able to hang on that long or might be senile if I do. If wiring is done to code then long wiring runs don't make a meaningful difference. Besides that AC induction motors are very tolerant of voltage variations. In most situations, the voltage can sag to about 105 volts per phase before motors start overheating from over current conditions.
Something else to consider especially with lathes -- the nameplate full power current is not the current being drawn except when it is being loaded to its maximum capability. Most of the time the current through the motor is a fraction of the maximum. Voltage sag only happens when the branch circuit is loaded down. Anybody who is really concerned could buy a digital meter and leave it plugged into the power line at their lathe. I suspect that most of us won't see a lot of drop in voltage -- maybe 5 volts, but probably not any more than 10 volts. If you see 15 volts drop, you might consider talking to an electrician about a solution.
