Motor swap in BIG Slider...?

[Malcolm McLeod]

Has anyone down-sized the motor in a BIG slider? Say dropped a 10Hp motor out and installed a 5Hp..??

I am casually looking for a used sliding table saw. Looking out to ~500miles from me, I see very few (=0) in a 'consumer' size: <=5Hp, 220V, single phase. But I see several industrial sized units: >7.5Hp., 480V, etc.. I don't need 10Hp, or even 7.5Hp - and really don't want to try to supply that much power via a home shop electrical service.

I am not concerned about the electrical reconfiguration inherent to such a swap, but as this is a new machine to me, I am wary of any potential mechanical pitfalls to reducing motor power.

TIA.

(I have considered a VFD and just dropping the allowed motor amperage, but want to consider the motor swap as well.)

[Erik Loza]

No firsthand experience but I would think it would be easier to get a phase converter. Most of the domestic 1-phase motors use a totally different mounting flange than the European motors. Just my thoughts.

Erik

[Mark Bolton]

Im outside your range, wish you were closer. Ive got an older Laguna 9.5' slider complete but taken apart, no motor, that they replaced for free that you could have for free lol. Been avoiding shipping it to scrap but its coming to that point to free up some space.

No idea on most sliders but even simple ones seem to have a bunch of relays and control circuitry for main and scoring motors and switched from a couple locations though as you say tossing on a new motor and throwing a switch on the cabinet somewhere wouldnt be an issue.

[Malcolm McLeod]

Thanks for the input. The shop service still has to feed the phase converter to feed a 7.5kW(10Hp) beast. And I can get custom motors - i.e. a euro 160M frame seems fairly common for the 7.5kW, so I could potentially get a 160M frame with 5Hp windings. ...thinking out loud.

But again looking for any limitations or gotchas in the mechanical side of this cerebral flatulence.

[Malcolm McLeod]

Thanks. The electrical side of this is what I do for a living, so not intimidated by that - - just never owned/operated a slider, so being cautious about the mechanical side and usage becoming a disaster.

[Kevin Jenness]

I don't think swapping the motor out would be practical, and finding a single phase motor on a "BIG" (?) slider is unlikely though not impossible. I would say it depends on your power supply and the specific machine you are looking at. I'm not sure where the price/ benefit ratio is for vf's vs rotary phase converters on motors over 5 hp. I have several vfds on 3hp or smaller motors and they are quite affordable. I put together a functional 10 hp rotary unit for under $400 which runs off a 50 amp 220v volt breaker. I would avoid high voltage motors personally due to the added complication of a transformer. If you can power a 7.5 or 10hp rotary converter that opens up many relative bargains in industrial scale equipment.

5 hp would be fine for most use, but extra power can be useful for big timber.

A free saw needing a motor changes the calculation entirely.

[Bill Dufour]

You can use a 3hp vfd to supply a 10hp motor and get 3 hp out of it. Just watch the voltage. Later on, if you need more power, you can buy a bigger Vfd and use the 3hp one for a drillpress or what ever. 3hp was the break point for vfds. above 3hp the price gets very high, very fast. It may be up to five hp now?
Bill D

[Brian Holcombe]

I would want that HP for the larger blades and bigger cuts. The large blades usually have a wide kerf which makes the HP requirement increase.

My friend Allen bought a Martin recently with 10hp iirc. I did some cutting on it of heavy material and it is nice to just cruise through those cuts.

[Malcolm McLeod]

I would want that HP for the larger blades and bigger cuts. The large blades usually have a wide kerf which makes the HP requirement increase.

My friend Allen bought a Martin recently with 10hp iirc. I did some cutting on it of heavy material and it is nice to just cruise through those cuts.

Thanks muy-cheesy-mas - - this is what I was looking for - the mechanical considerations! I did controls work for a lumber mill on a wide range of equipment - not a slider - with huge blades. But, I have never laid hands on a circular saw blade larger than 12", so didn't realize the 12"-18"(?) blades are wider.

Prompt for this musing was a rasher of Altendorf F90s on C.List recently. And for reference, intended use is furniture scale projects, not timber framing.

For the other responders, again thank you - - I have an excellent grasp (...well, at least my boss thinks I have) of the electrical side of this. And I simply don't want to feed a saw with 50A, regardless of the interface (rotary/static/vfd/3ph/1ph/etc). Ultimately, I may have to, but first exploring options to reduce this.

[Mark Bolton]

Typically anything larger that 12" diameter your just going for lower entrance/exit angles on veneers/sheet goods or if your for some reason cutting stacked sheets. Even then they usually max out around .180 but in my opinion for general use, sheets/solids up to 8/4 a 12" blade is going to do everything you need and the smaller the diameter the better your going to do with lower HP.

When I have a mile of heavy ripping to do in 6/4 or so we run a 10" .126 kerf blade to maximize the power of the saw and increase feed speed.

I dont honestly know of a situation other than fragile veneers and no scoring that you'd run 14, 16, 18 inch blades by default. The up front and sharpening costs alone dont really make sense unless you absolutely need it.

[Patrick Kane]

Thanks muy-cheesy-mas - - this is what I was looking for - the mechanical considerations! I did controls work for a lumber mill on a wide range of equipment - not a slider - with huge blades. But, I have never laid hands on a circular saw blade larger than 12", so didn't realize the 12"-18"(?) blades are wider.

Prompt for this musing was a rasher of Altendorf F90s on C.List recently. And for reference, intended use is furniture scale projects, not timber framing.

For the other responders, again thank you - - I have an excellent grasp (...well, at least my boss thinks I have) of the electrical side of this. And I simply don't want to feed a saw with 50A, regardless of the interface (rotary/static/vfd/3ph/1ph/etc). Ultimately, I may have to, but first exploring options to reduce this.

Yeah, some of the Altendorfs ive seen appear to be fantastic deals. Assuming the F45 is on a similar playing field as a Martin T72A, the prices are great. For example, Grothouse has tried selling their T72a with a 12' slider for $15,000 for 18 months. there is an Altendorf F45 with a 10.5' table in Ohio for $6,000. They are within 2-3 years of production from one another.

[Malcolm McLeod]

Typically anything larger that 12" diameter your just going for lower entrance/exit angles on veneers/sheet goods or if your for some reason cutting stacked sheets. Even then they usually max out around .180 but in my opinion for general use, sheets/solids up to 8/4 a 12" blade is going to do everything you need and the smaller the diameter the better your going to do with lower HP.

When I have a mile of heavy ripping to do in 6/4 or so we run a 10" .126 kerf blade to maximize the power of the saw and increase feed speed.

I dont honestly know of a situation other than fragile veneers and no scoring that you'd run 14, 16, 18 inch blades by default. The up front and sharpening costs alone dont really make sense unless you absolutely need it.

Thanks, I will add this to the data file. Would the arbor typically have the travel range to get full depth use of a 10" blade - - i.e. ~3" depth of cut (@90deg)? Or, does the large diameter arbor limit this?

I have previously skimmed over these larger Hp saws as unnecessary for my use, so have not even investigated the blade options and ranges available. They seem to be universally equipped/advertised with blades of 16"-18", so just assumed that was the standard.

[Brian Holcombe]

Typically anything larger that 12" diameter your just going for lower entrance/exit angles on veneers/sheet goods or if your for some reason cutting stacked sheets. Even then they usually max out around .180 but in my opinion for general use, sheets/solids up to 8/4 a 12" blade is going to do everything you need and the smaller the diameter the better your going to do with lower HP.

When I have a mile of heavy ripping to do in 6/4 or so we run a 10" .126 kerf blade to maximize the power of the saw and increase feed speed.

I dont honestly know of a situation other than fragile veneers and no scoring that you'd run 14, 16, 18 inch blades by default. The up front and sharpening costs alone dont really make sense unless you absolutely need it.

I use a 10” blade since that’s what works on my saw but I have found the larger blades useful for joinery work and light timber work.

[Kevin Jenness]

Prompt for this musing was a rasher of Altendorf F90s on C.List recently.

I believe the F90 is non-tilting. That would be a dealbreaker for me.

[David Kumm]

Swapping to a smaller motor is easier than going to single phase. Saws like SCM run 9 hp motors that are smaller frame and an easier swap for 5 hp, three phase. You still need a vfd but they will be in the 500 range. I have a 200 amp service in my house and the home shop is fed by 100 amps off the main and runs 9 hp motors with a 7 hp dust collector and I've not shut down the air conditioner or lights yet. Dave

[Malcolm McLeod]

I believe the F90 is non-tilting. ...


... I've not shut down the air conditioner or lights yet. Dave

Aware of the non-tilt, but it was the apparent surplus of this model that got me thinking in re-engine-mode. I was also thinking of the slider as replacement for my cabinet saw, but IF it came to an F90, it would probably be an augmentation instead.

I have 2 independently fed 400A panels in the house (@garage/shop), I think the A/C & lights are safe - even at 10Hp. I just can't get to a mental justification of it :: exploring options.:cool:

[Richard Coers]

"I am wary of any potential mechanical pitfalls to reducing motor power." What possible mechanical pitfalls could there be based on horsepower? User pitfalls, but mechanical?

[Malcolm McLeod]

"I am wary of any potential mechanical pitfalls to reducing motor power." What possible mechanical pitfalls could there be based on horsepower? User pitfalls, but mechanical?

3 types of data:
1-What we know; 2-what we know we don't know; 3-what we don't know we don't know.

I couldn't think of anything mechanical, but I'm trying to make sure there is nothing hiding in #3.:eek: Crowd sourcing can be a wonderful thing.

[Jared Sankovich]

Aware of the non-tilt, but it was the apparent surplus of this model that got me thinking in re-engine-mode. I was also thinking of the slider as replacement for my cabinet saw, but IF it came to an F90, it would probably be an augmentation instead.

I have 2 independently fed 400A panels in the house (@garage/shop), I think the A/C & lights are safe - even at 10Hp. I just can't get to a mental justification of it :: exploring options.:cool:


Wait, you have 800A of service to your house/shop/garage?

What mental justification do you need? Not trying to be smart genuinely curious.

[Malcolm McLeod]

Wait, you have 800A of service to your house/shop/garage?

What mental justification do you need? Not trying to be smart genuinely curious.

Yes, I know, it probably seems ridiculous...
I am not a pro. For the work that I do, any saw over 5hp would be like running to the corner bodega for a 6-pack in a Bradley Infantry Fighting Vehicle. Way cool. And doable. But not really socially responsible?

[Phillip Mitchell]

LOL, I was thinking the same thing. Seems like a decent RPC with a proper 3 PH MLO sub panel is the simplest move with that much available supply.

I have 200 amps of service to the house and use probably less than 100 amps max in the shop at any given time with the largest machines being run simultaneously being a 3 HP cyclone, 10 HP Kay RPC and either the 9HP planer or 9HP sliding saw. Seems a compromise to downgrade a decent sliding saw with a smaller motor even if you have no immediate intentions of using the full HP capacity. Just my opinion.

Is your primary aim with this project to save money or to be convenient or? What are all the costs associated with swapping the motor to a smaller 3 PH motor? Alternatively, you can buy 10 HP VFDs for around ~$850 or so the last time I checked. This is the threshold where it begins to make more sense to invest in RPC and supporting infrastructure especially if multiple 3 phase machines are on the radar.

[Kevin Jenness]

Yes, I know, it probably seems ridiculous...
I am not a pro. For the work that I do, any saw over 5hp would be like running to the corner bodega for a 6-pack in a Bradley Infantry Fighting Vehicle. Way cool. And doable. But not really socially responsible?

Yes, it does. Contrast the embodied energy in the motor and controls that will probably wind up in the scrapyard and the decreased utility of the saw to the next user should there be one vs the additional electricity you will use as a hobbyist. You want or need a BIG saw? Just accept that they come with big motors. Put the money you save into solar panels. Or take up Mark B's offer and save the planet from one more machine in the crusher. With 800 amps of service capacity maybe there's some other aspect of electricity usage that could be cut back.

[Bill Dufour]

My VFD knowledge is out of date. I looked today a 240 volt ten HP VFD is under $200 on the bay.
You may need at least a 10KVA transformer at about $400 plus shipping.
Bill D.

[Malcolm McLeod]

... primary aim with this project (thread)... ...is to learn something. Perhaps I should have bolded the casual nature of this inquiry. I don't even have a budget number yet.


Yes, it does. Contrast the embodied energy in the motor and controls that will probably wind up in the scrapyard and the decreased utility of the saw to the next user should there be one vs the additional electricity you will use as a hobbyist. You want or need a BIG saw? Just accept that they come with big motors. Put the money you save into solar panels. Or take up Mark B's offer and save the planet from one more machine in the crusher. With 800 amps of service capacity maybe there's some other aspect of electricity usage that could be cut back.

These will undoubtedly factor into any final decision. Mr. Bolton's incredibly generous offer, which I took as perhaps just a bit in jest - hence his "lol" - would require a 32-odd hour drive (based on vague recollection of a WV location in his profile at one time). Yes, I have considered it could be crated & shipped, as could several other machines outside my arbitrary 500 mile search radius. And while Mr. Bolton's history on SMC certainly elevates him in my eyes above ANY auction/online site, the pitfalls of buying sight-unseen from a stranger has been discussed in exquisite detail on SMC.

Jumping way outside the scope of my re-engine OP....
I used 500mi as a distance I am willing to drag a flatbed trailer - and then turn around and drive back empty handed, should a saw prove a lost cause on inspection.

I have looked for new - casually - at Grizzly (G0623X), SawStop w/ sliding outrigger (nixed :: too many compromises), Hammer K3/K4 family, & SCM SC3C/SI 400. Used searches yield virtually nothing in the range of these smaller machines (tho' I am not adept at auction house searches, or they're too far away). This brings me to the BIG (>7.5hp) used sliders that do seem to be more common. I don't need the physical size or Hp, but maybe a bargain? I can run them as-is, I can electrically limit them with a VFD, or I can down-size a motor.

And so back to my OP, any pitfalls to reducing motor power?

[Phillip Mitchell]

I feel like the pitfalls have already been outlined.

-Reduced power for deeper cuts
-Limited re-sale value to most who would be assuming the saw has the stock capacity of a larger motor
-extra cost/time of sourcing new motor, etc of the proper frame size and specs
-orphaning a perfectly good motor that was designed for a specific saw

I don’t think a VFD necessarily need be limiting. I can’t imagine even a 7.5 or 10 HP VFD being more $$ or harder to set up than swapping out for a new motor that may still need phase conversion, unless you just happen to have multiple candidates of suitable motors sitting around on a shelf for short money already.

Also, depending on what size stroke saw you actually need/want to acquire you might search for something like a Minimax SC3, which are often single phase and 3 or 5 Hp motors with a shorter sliding stroke. If you are patient and vigilant with different avenues of searching you will find something within range in time without having to devalue a bigger saw with a smaller motor, especially if this is more of a curious sort of thing and not an immediate need for a particular project / job.

[Mark Bolton]

Mr. Bolton's incredibly generous offer, which I took as perhaps just a bit in jest - hence his "lol"

The lol is just a goofy habit but I agree with all of your concerns. It was not an offer in-jest but agreed there may be more work in a free saw for something that doesnt "fit your bill" than you want to consider. That said, free is free but the miles are the killer. I dont doubt if you were 100 miles away it would thankfully be clean/clear/swept floor space by now ;-)

The killer in my opinion with most any of these scenarios is the mere cost of a good quality replacement motor swap, controls, perhaps having an adapter machined, and the perpetual elephant in the room... your time.... it very quickly lands to the proper decision being an auction machine that is pretty much plug and play/drop it on the floor, wire it, and go.

I kind of understand your logic a bit but on the flip side I cant really say that I'd be confident in happiness with a beast of a saw de-rated to a 5hp motor. That kinda speaks to not needing a beast of a saw but it its dirt cheap/scrap value (which is common) I guess it could make some sense. Ive seen numerous old sliders go for less than scrap but they are still fully assembled and ready to run.

[Gabe brown]

I put a 3hp single phase motor on an ancient scm slider. Works fine. I was lucky, when I went to mount the motor I discovered a previous owner had already drilled and tapped bolt holes on the motor mount for the same frame size motor I had bought.

[Warren Lake]

3 HP lesson motors have been under powered at times on my General cabinet saws. 3 Hp will work but if you are ramming material through in the real world I would want proper power. Think its 9hp on the one I have, stock motor would have to check too much sawdust in my memory.

[Michael Schuch]

Will the new motor fit in the physical space of the old motor?
Is the mounting the same on the new motor and the old motor?
Is the shaft length on the new motor long enough to locate the pulley properly?
Is the shaft the same diameter between the new motor and the old motor?
If the shaft size is different can you get a pulley that you can substitute for the original pully that fits the new motor and will the pulley line up?
If it is has multiple belts is the belt spacing on the new pulley and old pulley the same?
Is the new motor the same speed as the old motor?
Does the saw have a scoring blade? If so does it have its own motor or is it run off the main blade by a belt?

That is all I could think of.

I don't particularly care for static phase converters but if you are starting with a 10hp 3 phase motor and use a static phase converter (purchased or make your own) the motor should run at 2/3rds the hp it would run at on 3 phase. So 6.6hp and the required current and circuit and breaker would also be reduced proportionately. If you make your own static phase converter the size of the start capacitor you choose will determine how fast the motor starts which will also affect the initial peak inrush current during startup. 6.6hp should be plenty for a hobby shop. My two big table saws with 12"+ blades are 5hp and they are beasts that will chew through anything I throw at them even with a full kerf blade. My 10" Powermatic cabinet saw is only 3hp which has never been a problem since the thickness of the cut is limited by the blade size.


The soft start on VFD's greatly reduce the initial inrush current when the motor is first powered on.

If it were me I would use a static phase converter where the reduced hp and associated current would be an advantage instead of a disadvantage which it is usually considered. A static phase converter would also be the cheapest option by far unless you have a free single phase motor sitting around. I would stay away from any 480v 3 phase motors that couldn't be reconfigured to run on 240v three phase.

[Malcolm McLeod]

Thank you all for the information. As my goal was to learn something, I'll chalk this up as a success. Majority opinion seems to be I can down-size the motor, but shouldn't! Clearly, the spirit of Tim the Tool Man is alive and well (MORE POWER!!).:D

Mr. Bolton, you have no idea how close you came to a free cup of coffee, presented on your front porch Monday morning - live and in person. I even sourced the Texas Mesquite we were going to trade for your saw. And SWMBO said, "Sure", but reminded me that my 'tow vehicle' is with my son at college, 3 parties we're hosting, holidays, and the eleven-teen other time commitments I've made. I took my coat off and stopped humming 'Country Roads'.:( (Drugs may help with the depression?)

The miles ARE the killer. And a little bit wiser search goes on.