[OP]
Contributor
I have a 220v 3ph Clausing DP with a 1.5hp two speed motor. I would like to change it over to run on a VFD so I do not have to start the converter every time I want to drill a hole. So......
Will the two speed motor add any complications to adding a VFD?
Contributor
Based on my recent experience, you cannot have a VFD with a magnetic type switch in between the VFD and Motor. The VFD i have has 12V switching options to control the VFD remotely. I can turn it on, reverse, forward. I dont know if there was options for the speed though.Originally Posted by Larry Edgerton
Additionally, the VFD itself is a variable speed switch, you can set to whatever you want.
Here is a link to a discussion on another site.
http://www.practicalmachinist.com/vb...tactor-205361/
[OP]
Contributor
This DP does not have a magnetic starter. I do not want to change speeds with the VFD. The DP has a Reeves drive.
Contributor
It might be ok direct to the VFD then. Hook it up and try it. What VFD do you have?
[OP]
Contributor
I have not bought it yet, that is why I was asking. I just got off of the phone with Clausing and it will not be a problem so will order one today. Thanks.
Contributor
Larry, I probably wouldn't shift on the fly. Select the speed and stay with it until you shut the vfd off. I think some can be programmed to allow for momentary motor disconnection but above my pay grade so I just select the speed first. Dave
[OP]
Contributor
That is kind of what I figured I would have to do. The switch is a three position affair with fast and slow on the right and the left and off in the center.
Half of the windings do not work on slow, all on fast. on slow speed it is a 3/4hp motor, fast is 1.5 hp. I figured the dead spot in the middle would be a problem, but not hard to work around..
Contributor
opposite, two poles for fast, four for slow. Consequent wound motor for constant torque. 1800 and 3600 rpm. Dave
[OP]
Contributor
I thought it was the other way around, but that is the way the fellow at Clausing explained it. It does make more sense. How do the three speed motors work like on sliders? Is it a three speed motor or is it taken care of with pulleys.
Aren't you in the middle of tax season?
Also. I talked to a tech at Factorymation and he said that I would have to shut off the VFD to switch motor speeds, not a problem for me as I mostly leave it in High unless working with metal.
Last edited by Larry Edgerton; 03-06-2017 at 7:10 PM.
Member
In this case I believe the typical protocol is to connect to the slow speed, and run the hz up above 60 to get higher speeds. I'm not an expert though and did not sleep at a Holiday Inn so get confirmation.
Doug
[OP]
Contributor
Running a motor at either extreme of the VFD's rpm capability for prolonged time will create a lot more heat according to the techs at factorymation, so that is not an option. The DP has a machine specific motor I do not want to replace. Shutting it off and restarting is not all that hard. or just select the speed range before starting the the VFD. That is all I have to do to have both, and if for some odd reason I need to cut over 2000, or under 100 I can use the VFD for that.
I know people do it, I am just not willing. My only reason for doing it at all is so I do not have to start the converter to drill a hole. I had a single phase drill press for that until I gave it away last week, and I miss it.
Last edited by Larry Edgerton; 03-06-2017 at 8:00 PM.
Contributor
Usually you want to stay at high enough hz to help the motor with cooling and only overspeed for short periods as the volt to hz ratio doesn't keep up. If you have a motor that will handle it and 440 voltage, you can program a vfd so that 60hz is 50%. that will reduce the voltage to 240 under normal conditions but add voltage as you increase the hz above 60. I've not done it so talk to someone smarter than me if you try it. Dave
Member
I have the exact same piece of equipment you do. Wire the motor for high speed and connect the motor directly to the VFD. Use the drum switch for the low voltage controls. Have "fast" tell the VFD to run at 60 Hz and "slow" to tell the VFD to run at 30 Hz. This will replicate the original behavior of the unit and do so safely.
[OP]
Contributor
I did not do it that way because I drill some big holes in steel on occasion and wanted to take advantage of the motors low speed. I did it as David suggested, and I am the only one in the shop so it will not be an issue.
Contributor
I have always heard that. a two speed motor should be set up for high speed on the vfd. Switching will disconnect the vfd under load and it may burn out permanently. at the least it will trip out on speed switching and the motor restarted each time. If you run it too slow it will not cool enough. add a computer case fan for more cooling.
Probably get more power to the spindle if you toss the reavees drive and use a fixed pulley with vfd speed control. That reaves drive probably eats 1/2 hp or more.
This is not the 1920's anymore so i also recommend HSS drills. they came out during the Great War even if many sellers still try to claim carbon steel is so modern and wonderful.
Bil lD
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