VFD Choice

[Paul BarterParticipant @paulbarter66156]

Hello all, Can anyone help regarding the choice of inverter size, should the full load amps of the driven motor or its stated horsepower be the determining factor and should a margin of safety be applied in either case? Also the inverter I have bought after watching Steve Jordans review, states 3HP and 2.2 KW. with an out put of 12 Amps. I plan to run a 1.5 HP motor with a full load amps of 4.5Amps.Is too big an inverter a problem, or will this aparently generous excess capacity be beneficial?Thanks in advance to anyone who can guide me.

Paul Barter

[Paul BarterParticipant @paulbarter66156]

Amps or Horsepower rating?

[John HaineParticipant @johnhaine32865]

The motor will consume the power it needs to deliver to its mechanical load and dissipate in internal friction and electrical losses. As long as this is less than the rated power of the VFD it will be fine. I think you will find there is a current limit setting somewhere in the inverter setup, you could set this to perhaps 6A rather than 12. If the motor was just running but not connected to a lathe or other machine it would consume much less than its full rated power.

[john fletcher 1Participant @johnfletcher1]

You can set the inverter parameters to suit your motor name plate details. John

[SillyOldDufferModerator @sillyoldduffer]

Posted by Paul Barter on 03/07/2018 09:47:48:

Hello all, Can anyone help regarding the choice of inverter size, should the full load amps of the driven motor or its stated horsepower be the determining factor and should a margin of safety be applied in either case? Also the inverter I have bought after watching Steve Jordans review, states 3HP and 2.2 KW. with an out put of 12 Amps. I plan to run a 1.5 HP motor with a full load amps of 4.5Amps.Is too big an inverter a problem, or will this aparently generous excess capacity be beneficial?Thanks in advance to anyone who can guide me.

Paul Barter

Two potential issues:

• Sometimes equipment only works properly within a designed power range.
• Quite often in engineering it's not a good idea to overate one component in a system; ideally the whole should be balanced.

In this case I don't think either issue matters. A VFD is designed to work from zero to full-power. The only benefit is that it will run cooler than normal. The disbenefits are: you may have wasted some money because smaller VFDs are often slightly cheaper; the unit is physically bigger than it need be (so what!); there might be a bigger bang if you accidentally short it out (unlikely); and some risk of burning the motor out if you maintained full power after a stall.

Fortunately, if you adjust the VFD's parameter settings to match your motor as mentioned by John Haine and John Fletcher, even the possibility of bigger bang or stall damage fades into the background. Most VFDs are intelligent and can be programmed to respect the limits of the motor they are driving.

The only real problem may be understanding the VFD Manual!

Dave

[Paul BarterParticipant @paulbarter66156]

Thanks to John H. John F and Dave, I am reassured. This is a very basic and cheap chinese vfd but it works! nothing like the menu of parameters on the cub or imo boxes I use elsewhere but as Dave says so what! Just needed to be sure I was not about to release the magic smoke from my nice Brooks motor.

regards Paul

[John HinkleyParticipant @johnhinkley26699]

I, too, am reassured. I've just ordered a 1.5kW 3-phase motor and Huang Yang similarly rated VFD and pendant control for my mill. I'd be very disappointed if I managed to blow it up! Waiting for Fedex to deliver the motor right now.

John

[John HinkleyParticipant @johnhinkley26699]

Rather than start a new thread, I'll continue my little hijack of this one.

All the kit duly arrived and I've installed it and it's running. Only one problem – the potentiometer only has any effect over the first 30 or so degrees. That is, from position 0 to 2. The motor attains full speed at that point and turning the pot further has no effect. I feel there must be a parameter that needs changing, but I'm blowed if I can decipher the manual enough to discover what it is. Any ideas, anyone?

John

[SillyOldDufferModerator @sillyoldduffer]

Could it be they've sent you a log potentiometer rather than a linear? Log types change value rapidly at one end and slowly at the other. Does it have any markings?

[John HinkleyParticipant @johnhinkley26699]

Sod,

That's certainly something I'll check, although the pendant was purchased as a ready-made unit from an eBay seller, so I'd be surprised if that was the case. Something to look at tomorrow.

John

[Martin ConnellyParticipant @martinconnelly55370]

If the supply voltage to the high leg of the pot is higher than the voltage for maximum speed on the VFD you will get this problem. If the VFD only expects a value in the range 0-5V and the pot has 0-15V across it then after 30% of the pot's movement the VFD is seeing the voltage for full speed. Are there any parameters to change the speed select input voltage?

Martin C

[David JuppParticipant @davidjupp51506]

Check that speed input is set for Voltage, not Current – most units can work with either method, only the Voltage method is suitable for use with a potentiometer.

Also double check that you have wired the 3 terminals of the pot to correct terminals on VFD.

[John HinkleyParticipant @johnhinkley26699]

Martin,

The vfd is set to accept varying values of 0V to 10V and the pendant is connected to the vfd GND and +10v supply. I am unable to verify this voltage, because my multimeter has disappeared during the recent house move. I'll get a cheapo one this morning and then it will turn up. In the meantime, I'm doing a factory reset on the vfd and going through all the parameters again, as well as checking that the pot is, in fact, a linear one, as SoD suggested above.

John

[I.M. OUTAHEREParticipant @i-m-outahere]

I had the same issue with a Huanyang unit , the manual states the external pot should be X value ( 10k from memory &nbsp but it only worked over athe first third of its travell and i think i ended up wit a 100k pot .

This now makes me wonder if the internal and external pots are in parralel which would yield a 1/3 value ?

I still never got a 100% sweep from the pot but got close .

Have a look at your pot does it have an A or B next to the value ?

[Norfolk BoyParticipant @norfolkboy]

Hi, The value of the pot will not make too much difference. As long as you are using Voltage detection not current. There will be 0 Volt one end and 10 Volt the other. The slider will return from 0V to 10V across the sweep range regardless of resistance. anywhere from 1k to 20 k pot should be workable. Even if it's a log pot all that means is you will get a rapid change one end of the travel.

It is far more likely you will find one of your settings will be at 50% or thereabouts somewhere, and only changing across a range 0-5volt and then ignoring the 5-10 volt range .it's not uncommon for factory default to be odd.

Edit just read Martins post sayng the same thing(If the VFD only expects a value in the range 0-5V and the pot has 0-15V across it then after 30% of the pot's movement the VFD is seeing the voltage for full speed. Are there any parameters to change the speed select input voltage?)

Alan

Edited By Norfolk Boy on 14/07/2018 10:43:36

[Norfolk BoyParticipant @norfolkboy]

Hi …again, Not used a Huanyang but did consider them, I seem to remember reading something about them defaulting to 400Hz max speed because they are mostly used to run high speed CNC and 120 Hz min speed. Make sure your frequency parameters are set to more appropriate limits.

Alan

[I.M. OUTAHEREParticipant @i-m-outahere]

Bloody winky thing is haunting me !

[Clive FosterParticipant @clivefoster55965]

Building on Alans suggestion that the default setting is 400 Hz its possible that the currently set maximum speed parameter acts as a simple cut off effectively limiting the active range of the potentiometer. If this were the case full potentiometer travel should always give 400 Hz or whatever maximum but travel beyond that corresponding to the set maximum would be ignored. There are situations where a set-up of this sort makes sense but its a very inconvenient default for a general purpose VFD.

If it is a general purpose VFD I'd imagine there are ways of setting things up to something more sensible. It is of course possible that its special purpose device intended for computer or data link control so the potentiometer is merely a machine setting up / servicing aid. With more industrial devices data link or computer controlled VFDs are frequently significantly cheaper than their general purpose brethren.

If there are no suitable parameter changes then changing the pot value to hard limit the range as suggested by XD 351 looks to be the best solution.

Currently looking for 3 HP VFD myself and almost made an oopsie last night for a similar reason over an ABB device at a very attractive price.

Clive

[John HinkleyParticipant @johnhinkley26699]

Hi, all. I'm ( mostly ) sorted. The pot now alters speed throughout its entire range but I can only get up to 50Hz output. I need more twiddling to get higher, but meanwhile I'm happy to settle for that and change belt positions for the odd occasion I want a higher speed.

For the benefit of those following a similar route, here's what I did:

Bear in mind this is for a HY01D523B 1.5kW 2HP vfd only.

1. set the V1 – VR jumper to short pins 1 and 2. For external pendant control
2. Set Parameter 013 ( Pd013 ) = 8 Factory reset to start with all default settings.
3. Set Pd001 = 1 Select external control
4. Set Pd002 = 1 Speed control by external potentiometer
5. *Set Pd005 = 400 Maximum operating Hz
6. *Set Pd004 = 50 Base Hz
7. *Set Pd003 = 400 Main Hz
8. Set Pd144 = 1420 Rated motor rpm from motor plate
9. Set Pd014 = 2.5 Acceleration to speed in secs
10. Set Pd015 = 2.5 Deceleration time to stop in secs
11. Set Pd141 = 220 Motor rated voltage from motor plate
12. Set Pd142 = 7 Motor rated current from motor plate

 

Items 5/6/7 * must be done in that order. I don't know why but the manufacturer is specific on that point.

I don't anticipate running the motor at anything approaching 400Hz, so there could be some experimentation needed there. I'll try changing Pd004 to 400Hz as suggested on another forum to see if that gives me a higher frequency out put. ( Changing it to 100Hz, for example, stops the motor working at all. ) For the moment, I'm content to play with what I've got. I am not an electrical whizz and it's made my brain hurt.

John

For XD351 – leave a space before the closing bracket ( like this ) and you won't be bothered by the winkies.

Edited for spelling

Edited By John Hinkley on 14/07/2018 12:16:35

[Norfolk BoyParticipant @norfolkboy]

PD072 default is 50 Hz maybe up that to 120Hz

Alan

[John HinkleyParticipant @johnhinkley26699]

You could well be on to something, there, Alan. I'll nip out and give it a go. Thanks.

John

[John HinkleyParticipant @johnhinkley26699]

Well done Alan! I nipped and changed Pd072 to 120 and now I can run the motor to near bursting point. Give the man a coconut!

I'm most grateful for the advice and suggestions given by all.

John

[John HinkleyParticipant @johnhinkley26699]

While using the mill today, I kept getting an error code indicating an under-voltage on acceleration. This stopped the mill from working, so I increased parameter Pd014 to 10 ( seconds ) and likewise Pd015 to 10 for symmetry. Seems to have solved it.

John

[SillyOldDufferModerator @sillyoldduffer]

Is your mill on the end on a longish cable? Like an extension cord, or perhaps a shed at the end of the garden. If so, the voltage drop on the cable when you draw current to accelerate might be contributing specially if the mains happens to be on the low side anyway.

One of these will tell you how many volts are actually available when the mill is running. If the volts sag noticeably when you power up and accelerate increasing the size of the cable might help.

Dave

[John HinkleyParticipant @johnhinkley26699]

No. The workshop is my detached garage alongside the house. It is fed via an underground armoured cable of sufficient size, installed by one of the previous owners. The electrician who installed the extra lights and power points for me when we moved in seemed to think it would be ok for all my kit. I'll monitor the situation, however. Don't know what I'll do if it turns out it needs to be upgraded/replaced. Take up knitting, probably.

John

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