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View Full Version : New-to-me Bridgeport and VFD running for the first time.



jmarkwolf
02-18-2013, 07:10 PM
The Bridgeport I just bought from the pawnshop and new TECO VFD are now up and running, however the mill is running slow and backwards. Might well be "operator error".

I know that an option is to simply reverse any two motor wires to reverse the motor direction, but while reading the TECO "destructions" for this circumstance, it says to make sure that the "U, V, & W" wires are connected correctly.

There are only three wires exiting my motor, all are black, and none are identified. I know VFD's don't like switches on the motor wires, so I had initially moved them from their original positions on the switch, directly "across" the switch so they are now connected directly to the incoming motor power wires and the drum switch is effectively out of the cuircuit. I poked around inside the drum switch box looking for identifiers but no luck.

How do you identify the 3 identical unmarked black wires?

MaxHeadRoom
02-18-2013, 07:22 PM
To enable the FWD command for the right direction, just switch any two UVW motor leads.
You should not have, or need a drum switch in the motor leads?
They should be connected directly from VFD to motor.
Max.

_Paul_
02-18-2013, 08:02 PM
I have Tecos running both lathes and the Bridgeport why dont you fit a control pod and make use of the variable speed, reversing, Jog, DC injection braking etc?

You dont have to buy anything expensive I make my own pods and buy most of my switchgear from chinese suppliers on Ebay.

When I bought my first inverter I took some time and worked out the wiring on one of these things and with some "reverse engineering" on a bought control pod came up with the following schematic:

http://i1177.photobucket.com/albums/x358/Donkey0atey/Inverter_wiring_diagram_zps2e5e82cd.jpg

Paul

jmarkwolf
02-18-2013, 08:08 PM
They are connected directly. I said in the original post "I initially moved [the wires] from their original positions on the switch, directly "across" the switch so they are now connected directly to the incoming motor power wires and the drum switch is effectively out of the cuircuit".

I am just making use of the original drum switch enclosure.

I checked the spindle RPM with my Harbor Freight photo tachometer and it is right on at 320rpm with the belt in the lowest position, which is correct for the the low-speed range. So things are better off than I had feared!

I have to investigate the back gear drive now.

Still curious how to identify three identical black wires as to "U, V & W" designation.

_Paul_
02-18-2013, 08:11 PM
Slow running .... check the parameters on the drive if its a used unit the frequency could be set to anything.

You need your native 50 or 60hz to get the motors rated/original speed if you want more then change the frequency to whatever you think the motor might stand, be warned though the Inverters I have will let me alter the frequency as high as 200hz which means theoretically I could run a 3000rpm motor up to 12000rpm though I have no doubt that would be a recipe for mechanical disaster.

Paul

jmarkwolf
02-18-2013, 08:39 PM
I have Tecos running both lathes and the Bridgeport why dont you fit a control pod and make use of the variable speed, reversing, Jog, DC injection braking etc?

You dont have to buy anything expensive I make my own pods and buy most of my switchgear from chinese suppliers on Ebay.


Paul

Oh, I am going to. My red and green button switches and lever switch will be here tomorrow, and I already have the enclosure.

Just a need a little more time than the snatches I've been able to sneak away from my desk. I know... I'll just win the lotto!

I think I'm going to make use of the big electrical box containing the big contactors and fuses, etc., rather than set it aside as I had originally planned.

There is some sizable hardware in there I have not yet identified, probably relays. Seems to have something to do with original external start/stop controls. If I can remove it entirely I'll have room for the VFD. The VFD would be entirely out of view then. Is there a compelling reason that the VFD needs to be within sight?

lakeside53
02-18-2013, 08:44 PM
Still curious how to identify three identical black wires as to "U, V & W" designation.

There is no "standard". It simply doesn't matter. They only have context relative to each other.

BTW, you can also tell you Teco which way to rotate.

jmarkwolf
02-18-2013, 08:47 PM
Slow running .... check the parameters on the drive if its a used unit the frequency could be set to anything.

You need your native 50 or 60hz to get the motors rated/original speed if you want more then change the frequency to whatever you think the motor might stand, be warned though the Inverters I have will let me alter the frequency as high as 200hz which means theoretically I could run a 3000rpm motor up to 12000rpm though I have no doubt that would be a recipe for mechanical disaster.

Paul

Hi Paul

I played with the VFD speed control as well as belt changes. The VFD seems to be limited to between 5Hz and 60Hz. There's probably a configuration edit that's needed to get higher frequency.

The belt changes are surprisingly easy. Much more so than my mill/drill.

I did play with the back gear and seem to have all the speed ranges indicated on the label on the front of the head, as confirmed with my hand-held photo tach. Plus those provided by virtue of the VFD.

Got to get my remote panel built so I can reverse the motor direction more easily when switching the back gear in and out.

Great fun!

Don Young
02-18-2013, 08:56 PM
Just in case you don't already know, the Bridgeport runs in reverse when in the low backgear speed range. They generally had the switch marked for low and high speed but it actually reversed the motor.

Breze
02-18-2013, 10:48 PM
My mill set up with the VFD is pictured below.Granted I never have a reason to use the back gear and therefore in my set up one would only have to move two wires on the VFD in order to reverse the motor. I don't know much about the Teco vfds but if they offer a remote keypad then it's easy to set up a control enclosure that you can mount within arms reach in lieu of having the VFD close by.

I set my belt in a position that gives me a top speed of about 3500 rpm, however I hardly ever run at that high a speed, the the vfd will give you digital variable speed right at your finger tips and the forward and reverse option makes it easy to deal with the switching requirements.

Ron

http://i163.photobucket.com/albums/t320/ronbrese/Mill%20Move/DSC03082.jpg

http://i163.photobucket.com/albums/t320/ronbrese/Mill%20Move/DSC03085.jpg

big job
02-19-2013, 06:21 AM
I really wanted to go that route, but I would have to get into my drum switch and
remove it. I checked it out (drum switch) total nightmare. Nine wires tied to
three cramped in there no room no markings and the back door looks like
a Raytheon Univac. So RPC , nope I cant find a 3hp used motor around here so
I went static phase. Install in 5 minutes Im satisfied I dont see any difference
EXCEPT I have five motors, one main, two for the table, a coolant pump and
a oil pump. I quickly learned that the main (spindle) motor has to be on, then
the others will start and run fine. Im thinking somehow the main is acting like
a RPC for the others. Then if I turn off the main the other motors still run with
no change and they dont get warm. Anyone know if this is normal or did
I just get lucky. And I was given the SPConverter new in the box >lucky.