# Help with VFD selection...recommendations welcomed



## troutdreams (Aug 2, 2018)

Hello all- New member here in search of answers from experienced VFD users. 

I'm looking for:
1) VFD make and model suggestions for cabinet saw and dust collector
2) suggestions on the appropriate 'paddle style switch' for the VFD going on the cabinet saw

Background:
The cabinet saw has a 3hp Baldor motor (model 35A13-863).  208-220/440 volt, 7.8-7.4/3.7 amp.  3450 rpm.  "Cycle 60" (HZ?).     I assume it's wired to run the 208-220 but that's just my assumption (pulled from middle school shop class).   This is the VFD I'll want a paddle style "off / On" switch attached to VFD.  I'm assuming that I cannot wire the powermatic's existing on/off switch to the VFD, correct?

The dust collector motor is Dayton 3hp (model 3KW99).  The plate shows 208 / 230 volts.  8.6/8 AMPS.  I do not see where the FLA is listed on the plate.  RPM is 3525.  

Thoughts on ordering two Huanyang GT-Series 4.0KW 5HP vfds as suggested by their rep? That model ($195) lists 18.5 amps output power.  More than necessary? $200 x 2 is in the budget but I don't want to spend more than necessary, or worse- end up with the wrong model/maker.  My primary wants are proper sizing, durability, and external "on/off" controls.  

My hopes are to have everything needed on site.  I'll give the installation a go but planned on bringing an electrician in to install a second panel out in my garage/shop area.  So long as I have the right parts on hand..all will be good.    

Thanks for any recommendations!


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## Briney Eye (Aug 2, 2018)

Those both sound like single-phase machines, in which case you don't need a VFD, just 220V outlets.


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## pacifica (Aug 2, 2018)

You might consider a rotary phase converter since you probably wont use variable speed, soft start and stop, custom torque curves , etc that a vfd offers. I have both and can promise you there are a lot less headaches with  phase converter.
Doesnt seem anyone reputable recommends the huangyang.
I use hitachi and automation direct.Hitachi is more  challenging to program but offers more options(probably more than 500).
The company I bought the hitachi from offered some support but ultimately the problem I had I needed to solve myself.
Previous threads offer near unlimited ideas and support.You just have to find what is relevant for you.


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## ttabbal (Aug 2, 2018)

You have 3HP motors, why 5HP VFDs? I know some people like to de-rate them, but I don't see much point in that myself, particularly for home shop use. I run 2HP motors on 2HP VFDs without any issues at all, and I load the motor up a fair bit on the belt grinder. 

For switches, you want them connected to the VFD control inputs, NOT between motor and VFD. That's not how traditional 3 phase switches are run, but it's what you need for VFDs. The output from the VFD should run direct to the motor, no switches. On/Off and direction controls are connected control inputs on the VFD itself. The switch itself will work, though it's overkill. It's likely a well designed part though. For example, I have seen people run the stock switches that come on a Bridgeport mill to the control inputs. They work fine and feel nice. 

Wiring them sounds a lot more complex than it is. Just do one part at a time and test. I generally run power in/out and use the on board controls for basic testing and setup. And make sure you don't run power in to the outputs. That's the easiest way to let the smoke out. 

For specific VFD recommendations, I have only used the el-cheapo chinese units from ebay. They work fine for me. I only have about 6 months on the longest one in use, but it shows no signs of problems. They also cost about $70/ea for the 2HP units. You have to decide if the bigger name brand is worth that much more to you. 

I searched the motor model numbers, they are 3 phase. As for RPCs, they can be simpler to set up. If you aren't going to use the more advanced features like speed control, they might be a good option. I never see them go for less than a VFD, but if you're already looking at $400 it might be a good option. And you can keep the traditional controls for the machines. If you already have an electrician coming, you can even ask them to install a 3 phase panel and do it up nice.


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## troutdreams (Aug 2, 2018)

Briney Eye said:


> Those both sound like single-phase machines, in which case you don't need a VFD, just 220V outlets.



Sorry- post wasn't clear.    
Both motors are 3phase


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## troutdreams (Aug 2, 2018)

Yes, that particular 5hp VFD was a sales rep recommendation.  I was eyeballing their 2.2KW  3hp "HY" series and the rep redirected me when I about the right match for those two motors.  T've noticed Huanyang pushes the "GT" series (higher quality?) but the larger size was either an upsale or for reasons I don't understand.  Does the VFD output power (amps) need to exceed the FLA of the motor, and if so by how much?  

I'm clear on switch being connected to the input of the VFD.  (VFD direct to motor).  The type of switch I can use on a VFD model has been a point of confusion.  I've read low voltage and then also magnetic.  I guess the first thing is to review the directions then I'll shop for switches later.


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## troutdreams (Aug 2, 2018)

pacifica said:


> You might consider a rotary phase converter since you probably wont use variable speed, soft start and stop, custom torque curves , etc that a vfd offers. I have both and can promise you there are a lot less headaches with  phase converter.
> Doesnt seem anyone reputable recommends the huangyang.
> I use hitachi and automation direct.Hitachi is more  challenging to program but offers more options(probably more than 500).
> The company I bought the hitachi from offered some support but ultimately the problem I had I needed to solve myself.
> Previous threads offer near unlimited ideas and support.You just have to find what is relevant for you.


Thanks for the  reply.  I went through the rotary vs VFD decision when it was just the cabinet saw, and VFD made more sense.  Now that I have another 3 phase motor in the shop, maybe not so much.  If I remember this correctly I will need a find a larger 3 phase motor (5hp) to work in conjunction with the rotary panel, correct?  
I did scan through several pages on this site looking for general VFD manf recommendations and posts related to sizing.  Never found an actual search bar with filter but will look again.


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## ttabbal (Aug 2, 2018)

Any switch should do. It's low voltage, but a high voltage switch will work, it will just be bigger. I see no reason for magnetic. Heck, when testing wiring options, I just used wires with the ends stripped and touched the terminals. Simplest switch there is.  

For current rating, I would use anything rated at or above the motor current. 

For search, I find google the easiest. Try this.. 

site:hobby-machinist.com vfd recommendation


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## troutdreams (Aug 2, 2018)

ttabbal said:


> Any switch should do. It's low voltage, but a high voltage switch will work, it will just be bigger. I see no reason for magnetic. Heck, when testing wiring options, I just used wires with the ends stripped and touched the terminals. Simplest switch there is.
> 
> For current rating, I would use anything rated at or above the motor current.
> 
> ...


Thanks for clarifying the switch voltage requirements- makes sense now.  I'll pick up a $20 paddle switch and just follow the connection instructions.  
Also appreciate the google search term and will give it a try.  
No love for your bare wire terminal testing though


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## pacifica (Aug 2, 2018)

troutdreams said:


> Thanks for the  reply.  I went through the rotary vs VFD decision when it was just the cabinet saw, and VFD made more sense.  Now that I have another 3 phase motor in the shop, maybe not so much.  If I remember this correctly I will need a find a larger 3 phase motor (5hp) to work in conjunction with the rotary panel, correct?
> I did scan through several pages on this site looking for general VFD manf recommendations and posts related to sizing.  Never found an actual search bar with filter but will look again.


A rotary phase converter doesn't need to be any more amp output than your largest motor. I use one rpc for 5 machines since I never use machines simultaneously.My table saw is actually 7hp and I use a 5 hp rotary phase converter to no ill effect(10 years so far). Then I have 2 lathes with vfd's.
Vfd is extremely useful for a lathe.


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## macardoso (Aug 2, 2018)

I use VFD's quite a lot.  Size the VFD right to the size of the motor. Unless the VFD is crap, it will put put the power it is rated for no problem.

The brand of VFD you have looks decent, but make sure you can find instructions on how to set it up (enter the motor parameters).

Another place to look is at Automation Direct's GS2 line of VFD's.   A bit more expensive that you found, but they are also a legit US based company.

https://www.automationdirect.com/ad...ts_(115_-z-_230_-z-_460_-z-_575_VAC)/GS2-23P0



Edit:  The VFD will typically be looking for a start stop switch wired into it using 24V logic voltage.  Don't ever disconnect the VFD outputs from the motor under power (a 3 phase switch) or you can damage the IGBT's on the inverter from a high dV/dt spike.


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## Briney Eye (Aug 2, 2018)

troutdreams said:


> Sorry- post wasn't clear.
> Both motors are 3phase



I've got Teco/Westinghouse and Fuji VFD's for smaller motors running from 115VAC.  Happy with both of them; the Teco seems to have more programming "options", which wouldn't matter for your machines.  I wanted the speed control knob on the VFD, but you don't need that either.  The 3HP Teco L510 is more compact than the Fuji FRENIC, which you might care about.

I've had good experiences with Wolf Automation, and they carry just about everything available.


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## troutdreams (Aug 2, 2018)

Thanks for the tip on the Teco L510 and Fuji FRENIC; they're both about $227 apiece at Wolf.  That's not much more than the Huanyang model the rep suggested.  It also doesn't hurt that "Westinghouse" and "Fuji" are more familiar names to me.


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## pacifica (Aug 2, 2018)

troutdreams said:


> Thanks for the tip on the Teco L510 and Fuji FRENIC; they're both about $227 apiece at Wolf.  That's not much more than the Huanyang model the rep suggested.  It also doesn't hurt that "Westinghouse" and "Fuji" are more familiar names to me.


seems like wolf automation gives decent support, something valuable for a vfd install.


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## troutdreams (Aug 2, 2018)

pacifica said:


> seems like wolf automation gives decent support, something valuable for a vfd install.



...and that’s a VFD feature I’d be inclined to pay for


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## hman (Aug 2, 2018)

Maybe a bit redundant here, but possibly helpful.  A VFD typically has both high voltage (line power in, motor power out) terminals and low voltage terminals.  The low voltage (often 24V or so) terminals are used for start/stop and directional controls, as well as inputs for a speed control potentiometer.  As others have said, the motor power should be hardwired directly to the motor, with no switches, etc.  

If you do want to use existing controls (like a paddle switch), first remove ALL 110 or 220 volt wiring, then wire it into the low voltage system.  Speed can be set with front panel controls on the VFD (up/down arrow buttons on the Teco) if you don't want to add an external pot.  You can also use front panel buttons for on/off and direction if desired.  I've always put the VFD in an enclosure protected from swarf and used low voltage multi-conductor cable to go to an external control panel.  There are lots of options.


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## troutdreams (Aug 2, 2018)

hman said:


> Maybe a bit redundant here, but possibly helpful.  A VFD typically has both high voltage (line power in, motor power out) terminals and low voltage terminals.  The low voltage (often 24V or so) terminals are used for start/stop and directional controls, as well as inputs for a speed control potentiometer.  As others have said, the motor power should be hardwired directly to the motor, with no switches, etc.
> 
> If you do want to use existing controls (like a paddle switch), first remove ALL 110 or 220 volt wiring, then wire it into the low voltage system.  Speed can be set with front panel controls on the VFD (up/down arrow buttons on the Teco) if you don't want to add an external pot.  You can also use front panel buttons for on/off and direction if desired.  I've always put the VFD in an enclosure protected from swarf and used low voltage multi-conductor cable to go to an external control panel.  There are lots of options.





hman said:


> Maybe a bit redundant here, but possibly helpful.  A VFD typically has both high voltage (line power in, motor power out) terminals and low voltage terminals.  The low voltage (often 24V or so) terminals are used for start/stop and directional controls, as well as inputs for a speed control potentiometer.  As others have said, the motor power should be hardwired directly to the motor, with no switches, etc.
> 
> If you do want to use existing controls (like a paddle switch), first remove ALL 110 or 220 volt wiring, then wire it into the low voltage system.  Speed can be set with front panel controls on the VFD (up/down arrow buttons on the Teco) if you don't want to add an external pot.  You can also use front panel buttons for on/off and direction if desired.  I've always put the VFD in an enclosure protected from swarf and used low voltage multi-conductor cable to go to an external control panel.  There are lots of options.




Yes, I’ve seen the high and low voltage terminals and the wiring seems to make sense to me.  Thinking that I couldn’t use high voltage switches with the low voltage VFD terminals was my error.  
I’ll just wire up the saws existing on/off to the low voltage terminals on the vfd.


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## troutdreams (Aug 3, 2018)

Thanks to all for the information. 
I ordered 2 of the Teco-Westinghouse L510 from Wolf Automation and also tossed a 30 amp safety disconnect switch into the cart as well, thinking I'd feel better having it when changing those table saw blades.  May try mounting that at the entry way to the shop so I can just power down all the 220 finger-eaters, keeping the kids safer when I'm not in the shop.


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