VFD inputs

[Hood]

I am wondering what is normal for a VFD controlled by momentary buttons on the digital inputs.
For example if I have input 1 on a VFD connected to a momentary normally open button and I set it up for Run Forward will it run when pressed and stop when released?

 

[m_c]

Depends on how it's programmed.
I would expect Run Forward to be latching.
There is probably an option for Jog Forward, which sounds more like what you're wanting.

 

[Hood]

Aye, Jog Fwd would do but also need Jog Rev and trying to find a VFD that does that, most seem just to have a Jog option.

 

[daleyd]

There is usually 1 input that will need a NC input connected to your stop button which needs a high signal (ie stop button not pushed) to run, the momentary are run forward/run reverse.

 

[daleyd]

Look for 2/3 wire control selection.

2 wire is latching switches for f/r - 3 wire is momentary f/r and stop (generally)

 

[daleyd]

what vfd are you using?

Going back to your original question if programmed to do so then I would expect a momentary push on the fwd or rev button to run the motor and leave it running until the stop button is pushed.

 

[Hood]

Ok, trying to find something that will fit in the space and find suitable inputs is the problem, it is a bleeding headache

What I am needing is to control a landing winch with Up/Down buttons and I want to be able to set the accel and decel so that it doesn't jerk like it does at the moment so I thought a VFD would be ideal. It worked fine sometimes and others not. For example it would go up or down then next time when I released the down button it would stop and then reverse slowly until I pressed the button again but sometimes it would need the up pressed and released, there was no consistency.

 

[daleyd]

If you can get a vfd with a hoisting macro it would save a lot of grief.

They have settings for braking, ramps etc for exactly this sort of thing. Might be a bit dearer than your basic versions but might be worth a shot?

 

[Hood]

This Delta VFD seems to say it will do what I want but not sure if I am reading it right or even if it will fit in the space I have.

 

[Hood]

If you can get a vfd with a hoisting macro it would save a lot of grief.

They have settings for braking, ramps etc for exactly this sort of thing. Might be a bit dearer than your basic versions but might be worth a shot?

Ok, will try and search for something along those lines

 

[daleyd]

To me that looks like 2 wire control settings, ie it’s expecting latching switches for fwd/rev with no stop signal. Which might actually do what you want, but there may be other settings which need configuring to allow this. (Im not familiar with this brand so im just guessing really).

Im back in work Tuesday and can have a look at our (Schneider) stuff for something if you want? If you don’t want Schneider it might at least give you some pointers as to what to look for in other manufacturer’s ranges

Does your hoist have a brake fitted?

 

[Hood]

This is what it shows further on. Is that switch symbol meant to be momentary N/O?

Regarding the Schneider, that would be good, the biggest problem will likely be space, really need to measure tomorrow to be sure what I can fit in.
Input is 415v 3 phase, output the same and it is a 1.5kw motor connected to a worm gearbox so not much load on the motor.

 

[Hood]

Oh regards the brake, I don't think so, it is through a worm box with biggish reduction so...
The only wires going out of the box to the motor side of things seem to be the 3 phases and two wires to a NC switch which gets hit if the button is not released.

 

[daedalusminos]

I agree, they look like latching config inputs... As I assume are your buttons when held. Your overtravel switch might need some thought, how would you normally get out of an 'over travel' situation?

 

[Hood]

Overtravel worked well today, thankfully
I just have it wired into the Fwd button so it breaks that contact when it hits the over travel. That was how I was stopping it sometimes today, I would just pull the wire to the side so it opened the switch.

 

[Hood]

Just read again, regarding getting out of the over travel, because it only broke the contact of the Up button you can just press the Dn button and it will come off the overtravel switch.

 

[daleyd]

This is what it shows further on. Is that switch symbol meant to be momentary N/O?

View attachment 326124


Regarding the Schneider, that would be good, the biggest problem will likely be space, really need to measure tomorrow to be sure what I can fit in.
Input is 415v 3 phase, output the same and it is a 1.5kw motor connected to a worm gearbox so not much load on the motor.

I don't think it really shows a momentary switch (though agree that's the usual symbol for a momentary) i think its just a representation of a general NO contact to show the general wiring arrangement

 

[Hood]

But would that not be what I am wanting. Open and it is stopped, pressed and held it is running?

 

[daedalusminos]

It's showing NPN mode where the input is grounded to sink current through the opto coupler LED

 

[daleyd]

Yes, agreed - but I think you want a jog function as m_c said above rather than a traditional 3 wire system with momentary switches (ie with a separate stop button).

What you are doing is using a 2 wire system (for latched switches) and expecting it to work with momentary switches (again I’m only guessing from the vfd make but that’s how I see it?).

Is there any facility to change the mode of operation, on many you can select whether you want momentary or maintained operation of switches - it will be a parameter somewhere.