Thread: Help please! VFD SCM Braked Motor

Originally Posted by Bohdan

The motor plate gives the power factor as 0.8 so you have to divide the calculated current by 0.8 to get the actual current.

23A/0.8=28.75A

The 5kW I was referring to is the VFDs max Power output.
The VFD's current limit will also have an additional allowance for a factor over and above the 23A for certain period.

Just pointing out that a 5kw motor requires a VFD that is larger than 5kw (at least 6.25kw).

Originally Posted by Bohdan

Just pointing out that a 5kw motor requires a VFD that is larger than 5kw (at least 6.25kw).

Good point, but presumably on a quality machine the manufacturers have overspeced the motor.
Typical motor powers used on 12" combo machines is 3HP so a 16" machine should work OK using 4HP, With the VFD limiting the OPs motor to 5.3HP I cant see any probs.

Of all my machines on VFDs only the DC uses close to their original full motor powers at typical max loads @ 50Hz.

I've overspeced the motors on most of of my machines but this is to typically to make more power available @ <50Hz. The two motors I wish I could get more power from at low RPMS are my 2, 1HP GMF grinders but replacing their motors with those of higher power.

Only the DC @65Hz uses its full motor rated power (4HP motor on a 5HP VFD) but it's too loud inside the shed for me to use it so I limit the speed to 60Hz.

Originally Posted by DomAU

Three phase [power] is potentially years away as it wasn't in the cards unless I move given that I would need to get under about 10m of concrete to run a new conduit to the power pit - which I assume is going to be very cost prohibitive - but maybe i'll get a quote. Can't see it being less than $5-6k though.

Dom
In respect to connecting 3 phase power to your premises ...

How much spare capacity is in the existing conduit connecting your house/shed to the power pit?
If you already have 2 phases connected (2 active + 1 neutral) pulling a new 4 core line (3 active, 1 neutral) through the existing conduit should be both doable and very little upfront cost. And a heck of a lot easier than mucking about with trying to debug a 3-phase electro-braked motor running via a VFD. (40 years ago, my father installed 3 phase to his house -- to run an air con unit -- by pulling a new four-core cable through his existing underground conduit. The cost of installation was just the cost of the new cable plus the new connection.)

Of course, if the house+shed only has single phase connected, the existing conduit size might be too small to pull two additional cables through it.
But then runnmng a high current draw item could compromise the electrical safety of your entire house/shed

Originally Posted by ian

Dom
In respect to connecting 3 phase power to your premises ...

How much spare capacity is in the existing conduit connecting your house/shed to the power pit?
If you already have 2 phases connected (2 active + 1 neutral) pulling a new 4 core line (3 active, 1 neutral) through the existing conduit should be both doable and very little upfront cost. And a heck of a lot easier than mucking about with trying to debug a 3-phase electro-braked motor running via a VFD. (40 years ago, my father installed 3 phase to his house -- to run an air con unit -- by pulling a new four-core cable through his existing underground conduit. The cost of installation was just the cost of the new cable plus the new connection.)

Of course, if the house+shed only has single phase connected, the existing conduit size might be too small to pull two additional cables through it.
But then runnmng a high current draw item could compromise the electrical safety of your entire house/shed

Yeah if it were that easy I definitely would have connected three phase power. I was told by the Sparky that I needed 50mm conduit for 3phase and that my house only has 32mm. So i'd need to run new conduit and while i haven't gotten a quote yet, I imagine running 25m of undergroud conduit and under 6m of sloped driveway would be difficult/expensive. Otherwise, as you say it's just the cost of the new line and the connect/disconnect fee ($1500-) by the electricity provider- so around $3000-3500 total without the conduit.

Last update. The machine is working fine on the VFD. I havethe VFD set to stop the cutter in 2.5s now and not getting any over-voltage issues so could probably go more agressive but I don't see the point as that is quick enough.

I bought, connected and programmed a switch to turn the machine on/off at the machine and that was easy to setup and works great. I attached magnets to the back so i can attach it anywhere on the machine.

20220423_090532.jpg

Also just fitted a 500mm felder extension which should work nicely and waiting on a 1m extension with leg for the outfeed - which will really help with the 3.6m tops I need to make.

20220423_090507.jpg

So all in all i'm happy and thanks again for the advice amd help.

Cheers, Dom

so didn't have to do anything to the brake?

Originally Posted by havabeer69

so didn't have to do anything to the brake?

Yes, I removed it. Covered in a prior post in this thread. I physically removed the electromagnet and friction plate.

Does that machine have motor drive on the thicknesser?

Originally Posted by BobL

Does that machine have motor drive on the thicknesser?

No. That's why I opted for this one vs a larger SCM model above it with powered thicknesser height adjust etc - I knew that would complicate things a lot.

Cheers, Dom

Originally Posted by DomAU

Last update. The machine is working fine on the VFD. I havethe VFD set to stop the cutter in 2.5s now and not getting any over-voltage issues so could probably go more agressive but I don't see the point as that is quick enough.

I bought, connected and programmed a switch to turn the machine on/off at the machine and that was easy to setup and works great. I attached magnets to the back so i can attach it anywhere on the machine.

20220423_090532.jpg

Also just fitted a 500mm felder extension which should work nicely and waiting on a 1m extension with leg for the outfeed - which will really help with the 3.6m tops I need to make.

20220423_090507.jpg

So all in all i'm happy and thanks again for the advice amd help.

Cheers, Dom

How much did Felder slog for that 500mm extension? When i asked SCM about them for my machine they laughed them off as being a waste of time but i've found them handy. I have the Aigner Folding Extension Table for mine which is handy, easy to install/remove.

It cost about $580- for the extension, $130- for the mounting bar, and $45- for shipping so $755- in total. The longer 1000mm extension will be another $900 odd with the bar and shipping.

I looked at the Aigner extensions and have been considering getting one (two month wait on the Felder) but they don't look as robust as the Felder extrusions and don't appear to have the adjustments or as solid a clamping system - how do you find them? Would they do a great job as a Jointer outfeed table? Are they perfectly flat, strong and sit nice and flush with the outfeed? The Aigner would be about $400- shipped so would be significantly cheaper too.

Cheers,

Dom

Oh, and as for the 500mm extension. It obviously does flex a little if you apply force at the extremity, but I think it will be helpful for face planing longer boards and I think they are rigid/stiff enough to do a good job of this.

Cheers,

Dom

The Aigner is great for jointer outfeed imo.

These don't have to be inherently flat and stiff so the same degree as a cast iron jointer surface as long as they aren't causing the board to lift, the main area for accuracy is your main tables being flat, these tables are just there for added support rather than reference surfaces. In saying that, with my straight edge I can't see any light under it so that works enough for me. I mounted it similar to Brian in this thread so that was the hardest bit.
Aigner Extensions - How do they adjust?
Aigner tables

When I added the bar to my bandsaw to use the same aigner table, i put two set screws in the top surface of the bar that I can adjust up/down to get it perfectly level with the cast iron bandsaw surface.

here is some DIY inspiration for you if you want to go down that route. Hammer A3-31 Custom infeed/outfeed tables

Craftsman hardware here in Australia stock the Aigner tables. Price has gone up a bit since I got mine but that is happening everywhere.