Dake 350sa cold saw

[Ralphxj]

I just picked up a used Dake 350sa cold saw (I won't say how much I paid, but it's worth a "you ****"). Haven't got it home yet, it's still sitting in the shop at work, the holidays got in the way of bringing it home. I'm not sure if it wwas worked when it was taken out of service (no details were available when I bought it), but I know I will need a VFD to get it working and start testing it.

Anyone have any tips or info I need for this saw, or this type of saw? I'm new to using cold saws, and really don't have much of a starting point.

As for the VFD, it's a 3hp saw. Is this what I need: https://www.amazon.com/dp/B01IFEOVSE/?tag=atomicindus08-20

Here is the manual for the saw: http://www.dakecorp.com/uploads/pdfs/manuals/Technics-350-SA.pdf

Here are a could photos I grabbed when I picked it up:


Notice the box on the left side. The next photo shows the details of that. I need to pull the cover and see what is actually in that box. I don't see that box on any of the other photos I've found online.


I need to do more looking, but from what I can tell, this transformer on the side wasn't a factory installed item?? Is this piece needed, or was it something installed to work at the previous owners setup?

 

[Getusum111]

Those are nice saws! Congrats.

 

[LXCam]

That "box" on the side is a buck boost transformer. Those are installed to dial in the voltage to the machine where the line voltage is too high or low for the motor. You won't need it for what your going to do.

Btw, I'd most likely assume the other owners shop voltage was 208 and that motor needs a true 230-240 to work properly.

 

[Ralphxj]

That "box" on the side is a buck boost transformer. Those are installed to dial in the voltage to the machine where the line voltage is too high or low for the motor. You won't need it for what your going to do.

Btw, I'd most likely assume the other owners shop voltage was 208 and that motor needs a true 230-240 to work properly.

Awesome, thanks! Is it worth keeping for any reason since I don't have 3ph? Worth anything to resell or should I empty the box and reuse the box for another project?

 

[LXCam]

Yup, you might find a use for it at some point. You'll never be able to sell for anywhere near what it would cost to replace. Let's say you have a run that was 300ft and incurred a 20volt drop, you could use it to bump it back up to spec, **** like that.

 

[anndel]

Nice saw, you ****!

 

[Ralphxj]

Is that the correct VFD for that sized saw? Are the cheap import VFD's worth the lower price or are they still not a safe way to go?

Something like this:https://m.ebay.com/itm/2-2KW-3HP-VF...196433?hash=item33b5b9fa51:g:OGgAAOSwD~xZk7to

 

[cvairwerks]

Check the motor current rating to select the proper sized VFD. The first one you listed is only rated for a 10 amp draw.

 

[Ralphxj]

Check the motor current rating to select the proper sized VFD. The first one you listed is only rated for a 10 amp draw.

Is it based on amps or HP or both?

 

[manwithtools]

Is it based on amps or HP or both?

Actually both. The drive you referenced should work okay if your motor is a 240 volt three phase, which I suspect it is. Inefficient 3 hp 240 volt motor will draw just a bit under 10 amps, more modern efficient ones will draw much less than that.

Double check that the motor is wired correctly for 240 volts, I'm sure it is, but wise to check.

That VFD needs to be put inside an enclosure, particularly with the chips and dust from a metal fab area. Put it in a NEMA 12 enclosure, check the manual to see required enclosure size for clearance and heat dissipation.

Shop around for the enclosure, prices vary.

 

[cvairwerks]

The reason I said check the motor nameplate, is that the book on it lists using a 16 amp plug.... A bit of weird size....

 

[manwithtools]

Well, the manual also calls for a 5 wire system with neutral ,but only shows 4 wires like we would expect for a three phase machine.

The manual sounds very "Spanglish". Also it shows 400V, 50hz for power input. Something is not correct about that manual. Please post a picture of the motor nameplate when you can.

 

[manwithtools]

Hold the bus....

That machine has a two speed motor, while that might work okay, you are going to have to observe some precautions. There is also a single phase motor (pump?) and a transformer for the control circuit. A VFD may not be the best solution here, you might want a phase converter instead.

Are you sure that's the right manual for that saw?

 

[Ralphxj]

Manual is what Dake lists on their website and it looks like the same saw in most of the photos. Hopefully I'll get more photos and details tomorrow when I can look at the saw closer.

 

[Ralphxj]

Here are the details from the motor tag as well as the main saw tag from the front of the unit.

 

[manwithtools]

You have a three speed 220 Volt 60hz motor. You could use a VFD on this saw, but it will need to have some rewiring of the control and power circuits to do it correctly based on the schematic in the online manual you posted. If you have a different schematic than shown in the online manual, I'd like to see it.

 

[Ralphxj]

You have a three speed 220 Volt 60hz motor. You could use a VFD on this saw, but it will need to have some rewiring of the control and power circuits to do it correctly based on the schematic in the online manual you posted. If you have a different schematic than shown in the online manual, I'd like to see it.

That's the only wiring schematic I have. I need to really go over the saw to understand how everything works and how the power gets down to 24v for all the controls. Wiring the VFD into only the motor shouldnt be an issue once I know how to power the rest of the electronics!

 

[cvairwerks]

Fuse 2 feeds a stepdown transformer for the 24 VAC power. Fuse 3 is on the 24 VAC side.

 

[Ralphxj]

Fuse 2 feeds a stepdown transformer for the 24 VAC power. Fuse 3 is on the 24 VAC side.

Ok spent some time looking at the wiring diagram and it seems fairly straight forward! This is my first dealings with 3ph so I'm learning as I go. Looks like I can wire the saw with my 1ph 220 through L1 and L2 and then pull L3 after the VFD?

Stepdown transformer won't care if it's hooked to 1ph 220?

Looking at the diagram, should be able to power the entire saw off 1ph 220 and then run the VFD right in front of the main drive motor? I'm guessing the 3~ means 3ph and the 1~ label on M2 means 1ph in the diagram? I'm guessing M2 is the coolant pump?

 

[manwithtools]

You're on the right track with your explanation. If you want to have two speed functionality, you'll need to rewire the drum switch to switch control signals to the drive to select "hi" and "low", not to switch to different winding's in the motor. Good luck, if you need more input, post here and someone will chime in to help.

I'd wire the motor to the high speed winding's and use the VFD to slow it to the lower speed setting.

 

[Ralphxj]

Thanks to everyone! Might wire it up at work to 3 phase first to confirm it works before I chase my tail with the VFD if it's not functional to begin with!

Once I get the saw home, cleaned up and order some parts I'll post up my results or more questions when I'm ready to wire up the the vfd.

 

[Ralphxj]

Ok now that I have the saw home and everything cleaned up, I'm ready to get the VFD figured out.

My first question would be, why cant I just put the VFD in front of the 3 speed switch, feed the converted 3ph power into the switch just like it would have been if the entire saw was wired to 3ph normally? Also, what is the difference between the $100 VFD's vs the ones that are closer to $400? In the eBay link below, it looks like the control part of the VFD is removable to mount it away from the main unit, how much wire is normally included, just wondering about mounting it to the saw control panel with the main unit behind the panel with everything else.

This is the one I was looking at: https://m.ebay.com/itm/3KW-4hp-13A-...365087&hash=item4d69d3d5e8:g:Qs0AAOSw9idaMzxu

But I talked to a tech on a website that specializes in VFD's (don't remember the site right now) and they recommended this one: https://www.amazon.com/dp/B00UCGM0NC/?tag=atomicindus08-20

 

[manwithtools]

The main reason you can't put the VFD in front of the speed switch is that the VFD does not like the motor load to be taken away while running. If you were operating the VFD and motor together and you switched the speed switch it momentarily interrupts the motor connection, that will likely burn up the output transistors in the VFD - no more worky.

Also the VFD will not like having the other single phase motor connected to it's output, it would likely detect that as a phase imbalance or overload condition and fault out. Same goes for the 24 VAC transformer being part of the load.

In your case, a phase converter is probably simplest to retain all existing connections - simply use it to supply all incoming power at the disconnect switch. Or you could replace your speed switch with a VFD and only wire to one of the speed windings on the motor. You could then use the speed switch to select one of two preset speeds in the VFD by wiring it to the FVD inputs (using only one set of contacts from the speed switch for each speed). You would wire the speed select switch through the control circuit of the VFD, not the incoming or outgoing power - hope that is clear. Actual connections and programming will vary by FVD.

Of the two FVD's, I'd feel most comfortable about the Lenze version. It has fairly good documentation.

 

[Ralphxj]

After 18 months, I finally got the saw out of the garage and into the shop. Hopefully it doesn't take that long to hook up the power. I ended up going with a rotary convert (got a free 15hp motor) rather then the vfd. Hopefully the blade is still good, a new one will cost more then the saw did!