Vfd question

[Joshjosh]

Hi,

I'm looking to fit a vfd to my wadkin bzb 20 bandsaw, ( I'm currently running it off a static converter but not getting enough power from the motor)

It has a 1.5kw 3 phase motor, I'm looking at fitting an invertek ode 3.

My question is should I get the 1.5kw vfd that runs at 150% for 60 seconds and 175% for 2.5

Or will I need to go up to the 2.2kw and pay the extra cash?

My concern is the start up load and wether the 1.5kw vfd will cope?

Hoping someone may have experience with fitting these to a bandsaw and know what I'll need.

Thanks

 

[ChaiLatte]

Every VFD on the market has a 'ramp up' setting when starting the motor. This all but eliminates the spike in current demand on start up.

You might also need to set a ramp down on switch off, to prevent the inertia of the bandsaw wheels causing an overcurrent fault as they coast to a stop.

For a brand name VFD, one described as 1.5kW will be more than adequate for a 1.5kW motor. The only time it would be wise to oversize a VFD is if it is an AliBang special, where some of quoted numbers can be optimistic.

 

[sploo]

I have a number of the (relatively) cheap Huanyang VFDs, all 2.2kW rated, and being used on a table saw, 12" planer, large lathe, and a CNC spindle - all programmed with a little bit of ramp up and ramp down time. All working well, never tripped an MCB or RCD.

 

[Sideways]

I have about 8 ODE3 and ODE2 drives in my shed.
They sing a bit, but are well made. Especially the sealed outdoor variant.
I would have no worries using a 1.5kW drive to power a 1.5kW bandsaw.
Because you can tune the ramp up, there's no need to worry about startup surge.
The drive can be configured in fan, pump and general purpose modes. These have different overload profiles in the menu (pump or fan, I forget, allows 10% overload over a longer period). Leave yours in default "general" mode and the 150% 60 second overload capability will be fine. If you exceed the overload allowance, the drive just shuts off, it doesn't take any harm.

A motor for woodwork doesn't tend to run at full load current for extended periods unless it's on a pump or extraction fan (which is why there is a special overload profile for these) and the Inverteks are decently made unlike some of the cheap no name drives where you would want to buy a size or even two sizes up.

Don't buy an unsealed VFD (Invertek or alibang special) and install it where it will get full of dust. If you buy an open style drive you must put in an adequate size of box where air can circulate and the heat can dissipate through the walls of the enclosure.

 

[Joshjosh]

Great info thanks.

This is a decent brand I think, I've seen it recommended on here before and it's from UK seller. £290 Inc vat and dust/ water protected

Sounds like 1.5 will be fine then

Thanks

 

[Sideways]

They are a home grown company. Made in Wales. Recently purchased by a larger international outfit.
Like all the other good name brands their instruction manual runs to many pages and the drives include options to allow to be configured to work with many different control setups and applications.

 

[ChaiLatte]

All working well, never tripped an MCB or RCD.

Nor should they. There is probably more brain power in a modern VFD that took man to the moon.

The only time it might happen is if the VFD itself decides its time on this earth has ended.

For the purposes of enhancing our knowledge, could you connect the three output wires of your VFD together and switch on its output. My guess is the VFD will handle it gracefully (without fire, explosion or other histrionics) with a fault condition, with zero effect on the incoming supply.

 

[Spectric]

Do not forget to oversize the VFD, motor FLA x 2 and size the cabling to suit the VFD and not the motor FLA. In layman terms think of it as if you are a brickies mate and are having to keep three bricklayers supplied, you are working harder than any one of the three bricklayers.

Hitachi explains as

Some of the better drives out there are ABB, a really good product and having used them upto 500Kw and with no issues they are far better than much of the stuff from Aliexpress and such.

 

[stigg]

I ran my bandsaw off a Drives Direct converter and it ran perfectly. As mentioned by others above, if the converter is dedicated to the machine and you are not starting in DOL mode then the VFD can gracefully start and stop the machine, eliminating the inrush current normally associated with starting a large machine. Different machines with the same motor will have different starting requirements due to inertia. My planer used to black out two properties at a previous location, crashing the neighbor's computer! That made me really popular.
With the VFD my saw was up to speed in a couple of seconds and stopped well less than 5 so you would think your proposed model will be adequate. Personally -depending on a modest price increase - I would always go with the oversized model just to be sure, but that's just me.

 

[Fergie 307]

I have a number of the (relatively) cheap Huanyang VFDs, all 2.2kW rated, and being used on a table saw, 12" planer, large lathe, and a CNC spindle - all programmed with a little bit of ramp up and ramp down time. All working well, never tripped an MCB or RCD.

Another vote for the Huanyang. Never had an issue with any of mine. Loads of options in the setup, and easy to configure. Just make sure to buy from a reputable source as apparently these are now popular enough to be being faked, I guess by other Chinese companies, which is quite ironic

 

[sploo]

Nor should they. There is probably more brain power in a modern VFD that took man to the moon.

The only time it might happen is if the VFD itself decides its time on this earth has ended.

For the purposes of enhancing our knowledge, could you connect the three output wires of your VFD together and switch on its output. My guess is the VFD will handle it gracefully (without fire, explosion or other histrionics) with a fault condition, with zero effect on the incoming supply.

To be fair, I can get the one in my lathe to trip out (the VFD, not the MCB or RCD) if I suddenly reduce the rpm with something heavy on the spindle; but I suspect I could fix that by adding an optional braking resistor. I've not installed one because I should just disengage the lathe's clutch rather than quickly reducing the rpm, but I every now and then I do forgot. I usually just have to power cycle the VFD to get it running again.

 

[Spectric]

these are now popular enough to be being faked, I guess by other Chinese companies

If it can be faked then it will be, this causes major issues when working within any industry that is tightly regulated because everything has to be quality assured and traceable, there has been everything from fake cable marked up as Pirelli to large softstarters impersonating the likes of Abb and Siemens. These fakes are also really good, so good that in many cases only the OEM can distinguish a difference and I dare say that the market is flooded with dangerous fake electrical goods. Another aspect to this is that even some genuine articles can become compromised because of substandard components finding there way into the supply chain, it only takes a cheap poor quality capacitor to make a high quality item not much better than a cheap asian import. On this level they like to sell fake electrolytic capacitors that have a really poor ESD and ripple current rating as being a far superior component and also Tantalum bead capacitors that have a voltage rating they do not deserve.

 

[Fergie 307]

One really dangerous example I have come across is sub standard petrol pipe. Had to replace a line in the Jeep and bought the correct spec high pressure pipe from a good local motor factor. Fortunately I had some other work to do about six months later, and noticed some surface crazing on the pipe. When I moved it it fell apart. Appeared to have degenerated owing to the petrol. Talking to a few people in the trade this has become quite a problem. Loads of this stuff about, all carrying the appropriate marks etc, but made of completely the wrong materials. It appears to have got into the chain somewhere so people can buy and supply it in good faith thinking it's genuine. Had this failed whilst I was driving then I would have had petrol at 70psi spraying out all over the place, with predictable results.

 

[Sideways]

Had this failed whilst I was driving then I would have had petrol at 70psi spraying out all over the place, with predictable results.

Decades ago I had this happen to me on the motorway with my wife to be and two friends in the car.
We smelt petrol, luckily were almost on an exit so I cut hard over and off the motorway.
Stopped ASAP, looked under the bonnet and the high pressure hose feeding the injectors had split and was spraying fuel over the engine.
By a miracle it didn't catch light but the RAC call handler couldn't believe this and kept asking "are you sure you don't need a fire engine ?".

 

[Fergie 307]

To be fair, I can get the one in my lathe to trip out (the VFD, not the MCB or RCD) if I suddenly reduce the rpm with something heavy on the spindle; but I suspect I could fix that by adding an optional braking resistor. I've not installed one because I should just disengage the lathe's clutch rather than quickly reducing the rpm, but I every now and then I do forgot. I usually just have to power cycle the VFD to get it running again.

My biggest one is a 4.2 on a 3hp metal lathe.
Always believe in overspec just to be on the safe side. Impressed that as it comes it will bring a heavy chuck to a stop in a few seconds, never had to add to it to improve the braking. And cost £130 a few years ago now. Only issue I had was the Chinglish instructions were a bit confusing in places, I had to actually set up and test a couple of functions to make sure they did what I thought they would. Overall very pleased with it.