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New to me RF 45 ..... In the shop

Some of these motors are star wound. They need a fairly balanced 3 phases to work properly. The VFD would be the better option unless you buy a commercial rotary phase converter that has this built in.
I have both in my shop and the VFD are nice for specific motors that you want to control.
 
Susquatch said:
I'm not sure I follow all that. I don't know why sourcing switches from the VFD is a problem. I think it's an advantage.

No VFD I ever saw would start after a power outage without first turning it off. VFDs contain all the safety features normally implemented through relays and control systems.
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Please be careful about VFD’s not starting after a power outage! Some units can be programmed to restart after a power outage, and can be set up to restart motor after a programmed amount of time when power returns, in hand with ramp ups of speeds to last operating speed, or near no ramp up to last speed.
Most all of our pumps, air blowers could/would do this, and all of this was utilizing mag switch’s in the controls, NOT requiring switching to off manually before restarting.
This was checked when doing a backup power test, power from diesel generator.
Now if VFD’s all have capability or not, I do not know. Possibly depending on switching wired in, controls,— (safety’s), and if has the ability of needed programming, and programming done. ( used VFD? Could be a surprise). At least 4 different makes/brands and sizes had this ability that we were using.
a question for a much more knowledgeable person or electrician, with VFD experience, more then mine!
 
Sinking or sourcing refers to the type or configuration of the transistors used for the low voltage DC inputs.

Sinking = NPN transistor = “switching the negative”.

Sourcing = PNP Transistor = “switching the positive”.

Some VFD’s have configurable input types with a jumper or small switch, allowing you to select which type works better for your application.

Most “North American” or European drive brands default to sourcing.

A lot of Japanese brands default to sinking.

Most full featured VFDs have restarting after a power outage as a selectable option. So certainly be careful with that one. A live test shouldn’t harm anything. A contactor on the line side is a way to ensure it does not restart, but word of warning, the contactor should not be used to start and stop the drive under normal circumstances. It can be used as an E-stop or a power outage safety mechanism. If used as an Estop mechanism most drives also have options for configuring this as well.

The low voltage inputs should be used to start, stop, and control the operation of the drive under normal circumstances.

Hopefully this helps you out.

@Susquatch that should answer everything?
 
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Bandit said:
Please be careful about VFD’s not starting after a power outage!
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That is true. Good point. On mine, it is a user choice. But that still meets the safety requirements. Any control system for a system without a VFD can do the same thing. The only difference is hardware control system design vs VFD Programming.

The point is that the VFD replaces the system in the control box.


.
 
BaitMaster said:
Hopefully this helps you out.

@Susquatch that should answer everything?
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Yup. I just wasn't sure where the terms came from or what they meant in the context of electrical control systems.

Your explanation makes absolutely perfect sense to me. Especially since those are the two main ways of powering a relay even without a VFD.
 
I have one of those drives on my shelf for my mill. When I get a chance to mount the 3ph motor. Be awhile for me as I’m using the mill for my little Webster project. I put 3 wire motor control on my lathe, the AT5 inverter I used doesn’t actually support it. So I used relays and 5vdc power supply for the control circuit. Then switched the inverter control through my original fwd rev switch and the relay contacts. Regular start stop operation from the push buttons. If I switch the original fwd rev switch to center the lathe shuts off. Can’t accidentally go from fwd to rev. As others have said don’t kill power to the drive, worse if it’s under load. Even industry drives don’t take it well. really bad is switching between the motor and drive.
 
Susquatch said:
Most VFDs will allow that and handle it quite well. I'm not saying you should do that, just that you could if you wanted to.
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I agree most, for sure industry or good name ones like Teko . Just not gonna take the chance with a 50 dollar Amazon one.
 
Still gathering parts n' supplies to get this mill running . I have a Huanyang 2.2 kw VFD , some cable , terminal strips , an E stop button , a junction box , a 24 volt digital tachometer and more .
I have gutted all of the old stuff out of the machine , the contactors , switches etc .

I kinda have a plan , gathering my info online because I am well outside of my comfort zone on projects like this , the end goal is to have it look professional , not like Homer Simpson was working on it .

I'm working on it when I have time , still working out a few details and not real sure about how I'm going to wire it . I want to use forward & reverse switches and an E stop button , like it was configured originally on the original panel , but wired to the VFD . I will need to figure out how to wire the FWD / REV switches , I am going to order new switches , the original switches are kind junky , I am not sure which switches I'm going to need just yet .

I also have a 24 volt digital Tachometer that I'd like to use , I still need to figure out how I'm going to mount the magnetic pickup , also , I am wondering if I can get my 24v from the terminal strip right on the VFD ?

Here's some of the old parts removed , the transformer , contactors , switches etc ........

IMG_5778.JPG

I have other things going on as well ....... the framers were here yesterday and the garage repairs have begun .......... YAY !
March 19 - 1.JPG
 
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I'm far, very far, from being an expert. But in my struggles, I did learn my VFD has a 24 volt output. When that is used. it's called source wiring. That was how I wired my switches for my lathe. You can use ordinary machine switches. I'm not sure that would be enough for your tach, though

A VFD would be deluxe. A high speed for wood inletting would really be nice.
 
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Gearhead88 said:
I'm working on it when I have time , still working out a few details and not real sure about how I'm going to wire it . I want to use forward & reverse switches and an E stop button , like it was configured originally on the original panel , but wired to the VFD .
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Sometimes you guys make me laugh. Not in a derogatory way. Just affectionate humour. You embrace CNC like hot chocolate but wiring up a VFD system makes you nervous.

Gearhead88 said:
I will need to figure out how to wire the FWD / REV switches , I am going to order new switches , the original switches are kind junky , I am not sure which switches I'm going to need just yet.
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I hate junky feeling switches too. There is something about a nice solid switch that just feels awesome - even if it's just switching a few milliamps.

Fortunately, you can use a big switch to handle low currents and it will work just fine. Just not vice versa. When and if you find some nice ones, please share.

Gearhead88 said:
I also have a 24 volt digital Tachometer that I'd like to use , I still need to figure out how I'm going to mount the magnetic pickup , also , I am wondering if I can get my 24v from the terminal strip right on the VFD ?
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Most likely you can. Tachometers usually draw very minimal current. If the VFD has a reference ground for the 24V supply, you should use that as the negative for the tach too.
 
Susquatch said:
Sometimes you guys make me laugh. Not in a derogatory way. Just affectionate humour. You embrace CNC like hot chocolate but wiring up a VFD system makes you nervous.



I hate junky feeling switches too. There is something about a nice solid switch that just feels awesome - even if it's just switching a few milliamps.

Fortunately, you can use a big switch to handle low currents and it will work just fine. Just not vice versa. When and if you find some nice ones, please share.



Most likely you can. Tachometers usually draw very minimal current. If the VFD has a reference ground for the 24V supply, you should use that as the negative for the tach too.
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Mmmm hot chocolate!
 
There is something about a nice solid switch that just feels awesome
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I didn't merely hoard, but sought out genuine IBM keyboards until I simply could no longer find any, and my last one died. I really don't like typing on what passes for keyboards these days.
 
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