Grizzly Bandsaw Questions

[David Markowitz]

Back again with dum bandsaw questions:

(1) Anyone have experience running at Grizzly GO513X2 or GO457 (both 2hp) on a 20A/110v circuit?

Both have a disagreement between catalog specs (20A/110v) and manual requirements (30A/110v). I called Grizzly technical support and was told that the specs had changed and 30 amps are required. I confirmed the change was in the specs, not the saw, making me wonder if there's a whole bunch of 513 and 457 owners happily using with 20A circuits, oblivious to the paperwork.

(2) Stepping down in power, I'm looking at the Grizzly GO555x (14A/110v). There's discounts this weekend on the Rikon 10-325 and the Powermatic 14 inch with a riser block, but the Grizzly seems to get marginally more love. Is anyone aware of a compelling reason *NOT* to go with the Grizzly?

(3) If I were to go with a 1.5 hp 14" bandsaw, what would be the CFM for dust collection?

Thanks in advance.

[Mark Ashmeade]

A "2HP" motor is a 1500W device, give or take the odd Watt.

As P=I x V, I=P/V. I=1500/120. I=12.5A

Thus the maximum draw of the saw is 12.5A. It won't run at anything like that under normal load, only when pushed. Instantaneous startup current may spike beyond 12.5A, but will quickly settle down. I'd expect the saw to draw in the region of 5-10A unless taxed heavily. Hope this helps.

I have a G0513P, but it's only ever been wired 240.

[Neil Brooks]

To the second part of your question....

I LOVE my G0555X -- upgraded with Carter Ratchet Rod, Cobra Coil Spring, guide BLOCK (vs. bearing) holders, and Carter Cool Blocks, the riser kit, and my 1/2" Wood Slicer blade.

That said, others love their 10-325 (is that right ?) Rikon, and ... if memory serves ... you get full resaw capacity without the need to install a riser kit.

I'm not sure you can go wrong with either, based on customer feedback as I'VE seen it.

But ... I agree with Mark's assessment of your current load situation on a 2HP saw.....

[David Markowitz]

Neil/Mark: I guess what I was asking, for practical purposes, is the manual's assertion that a 30A/120v circuit for the 2hp saws overkill? I'm getting from Mark's post that it would be overkill, and only the torque strain of startup or resistance on a cut would test the upper bounds of a 20A circuit.

@Neil: the Grizzly's 555X is to the 555 what Rikon's 10-325 is to the 10-320--a 14 inch bandsaw with an extended column which doesn't require a riser block to get a higher clearance. It includes a resaw fence, too. I'm guessing, based on the context of adding a riser block, that you have the 555.

[Prashun Patel]

@Neil: the Grizzly's 555X ...[has]... an extended column which doesn't require a riser block to get a higher clearance.

I'm not sure I understand. The G0555 and G0555x both have 6" max cutting height. I always thought the FRAMES were identical between the 2 saws. It's just the motor and the bells and whistles. The table's a little larger too. happy to be told otherwise, though!

For this reason alone I would be tempted to go with a 17" saw. You can certainly get by with a 14" saw, but I've wanted for more saw many a time....

I have the G0555.

[Tom Cornish]

A "2HP" motor is a 1500W device, give or take the odd Watt.

As P=I x V, I=P/V. I=1500/120. I=12.5A

Thus the maximum draw of the saw is 12.5A. It won't run at anything like that under normal load, only when pushed. Instantaneous startup current may spike beyond 12.5A, but will quickly settle down. I'd expect the saw to draw in the region of 5-10A unless taxed heavily. Hope this helps.

I have a G0513P, but it's only ever been wired 240.

This is unfortunately an oversimplification. The theoretical work capability of a 1HP motor is 746 watts. Motors are far from 100% efficient, however, and substantially more energy input is required to get 746 watts of mechanical energy out. Motor type, condition, and initial quality also cloud this issue.

A safer number to use is about 1000 watts/HP for a heavily loaded motor (tuned dust collector, saw doing a heavy cut, etc.). This estimation can be refined by looking at the motor nameplate. A high quality motor will likely consume a couple amps less for the same work output as a junko motor.

It still seems that a 2HP motor should have no trouble being powered from a real 20A 120 volt circuit, so I agree with other posters in that regard. If you do have trouble, you can just let off the feed pressure and your current usage will drop.

[David Markowitz]

I'm not sure I understand. The G0555 and G0555x both have 6" max cutting height. I always thought the FRAMES were identical between the 2 saws. It's just the motor and the bells and whistles. The table's a little larger too. happy to be told otherwise, though!

For this reason alone I would be tempted to go with a 17" saw. You can certainly get by with a 14" saw, but I've wanted for more saw many a time....

I have the G0555.

You're correct. I'm dizzy on specs now :)

[Mark Ashmeade]

Tom,

I'm afraid I have to disagree with you. I only ever assume the input power to be what's on the plate. It would be dangerous for a manufacturer to state that the output power is X Watts or Y HP on the plate, since as you rightly say, no machine is 100% efficient. If it were, the machine would always draw more current than the rating plate, and that is a no-no.

While the whole subject is as complicated as one wants to make it, I would be very surprised to see a modern motor (say the last 30-40 years) display the output power as opposed to the input power requirements.

All this "true HP" malarkey is irrelevant when rating the supply to a machine. It doesn't matter if the machine is a poor 10% efficient. If it says it's a 10A machine, it should never draw more than that (startup excluded). Whether it cuts well is an entirely different story, however.

[Jim Rimmer]

Back again with dum bandsaw questions:

(1) Anyone have experience running at Grizzly GO513X2 or GO457 (both 2hp) on a 20A/110v circuit?

Both have a disagreement between catalog specs (20A/110v) and manual requirements (30A/110v). I called Grizzly technical support and was told that the specs had changed and 30 amps are required. I confirmed the change was in the specs, not the saw, making me wonder if there's a whole bunch of 513 and 457 owners happily using with 20A circuits, oblivious to the paperwork.

(2) Stepping down in power, I'm looking at the Grizzly GO555x (14A/110v). There's discounts this weekend on the Rikon 10-325 and the Powermatic 14 inch with a riser block, but the Grizzly seems to get marginally more love. Is anyone aware of a compelling reason *NOT* to go with the Grizzly?

(3) If I were to go with a 1.5 hp 14" bandsaw, what would be the CFM for dust collection?

Thanks in advance.
I have the Grizzly G0555X and really like it. It tunes up easily, has a bigger table, and more HP than the G0555. I bought some woodslicer blades and it resaws like a dream. Unless the design has changed it does not have 12" resaw capacity without the riser; mine is 6" resaw which is all I nneed right now.

I am a hobbyist so it comes down to your usage but i would recommend the G0555X.

[Lance Norris]

I have the 457 and it also is excellent. Its wired to 220 so I have no input there. But as far as performance, features and ability, Id put it against any 14" saw and be surprised if it lacked in any way(aside from 13" resaw of the Rikon).

[Tom Cornish]

Tom,

I'm afraid I have to disagree with you. I only ever assume the input power to be what's on the plate. It would be dangerous for a manufacturer to state that the output power is X Watts or Y HP on the plate, since as you rightly say, no machine is 100% efficient. If it were, the machine would always draw more current than the rating plate, and that is a no-no.

While the whole subject is as complicated as one wants to make it, I would be very surprised to see a modern motor (say the last 30-40 years) display the output power as opposed to the input power requirements.

All this "true HP" malarkey is irrelevant when rating the supply to a machine. It doesn't matter if the machine is a poor 10% efficient. If it says it's a 10A machine, it should never draw more than that (startup excluded). Whether it cuts well is an entirely different story, however.
My beef is not with the nameplate ratings, but your rule of thumb that a 2HP motor draws 1500 watts.

People commonly say that "1HP = 746 watts". This is true, but this a rating of mechanical power. In the case of an electric motor, due to the inefficiency of energy conversion, it takes more than 746 watts electrical input to make 1HP (746 mechanical watts) of output.

I took a brief survey of a few motors I could easily access in my shop (nameplate ratings):

Sawstop 5HP single phase TEFC: 19.7A 240V = 945 watts/HP
Clearvue cyclone 5HP single phase Leeson TEFC: 21A 240V = 1008 watts/HP
Bridgeport mill - 2HP 3 phase TEFC: 5.6A 240V (5.6A * 240 * 1.73) = 1162 watts/HP
MK Diamond tile saw with 1.5HP Baldor TEFC: 14A 120V = 1120 watts/HP
Freud 1700 router 2.25HP 13A 120V = 693 watts/HP (peak horsepower - an "optimistic rating")

You can see from my small list that 1000 watts/HP is a better guess, and even that may not be enough for motors with poor efficiency. The only motor that comes anywhere close to 750 watts/HP is my router which has a brushed non-TEFC motor. It's clear that they are measuring the "horsepower" based on input current draw, and rounding up even there to come up with "2.25HP".

[Thomas L. Miller]

I have the GO555x with the riser block. I use a Woodslicer 1/2 blade and it resaws nicely as well. No complaints about the saw or the blade. Timberwolf blades are a different matter. I have a 3/4 inch that I'd be happy to send to anyone who wants it. It does not work on my saw.
Regards,
Tom

[Rod Sheridan]

Tom,

I'm afraid I have to disagree with you. I only ever assume the input power to be what's on the plate. It would be dangerous for a manufacturer to state that the output power is X Watts or Y HP on the plate, since as you rightly say, no machine is 100% efficient. If it were, the machine would always draw more current than the rating plate, and that is a no-no.

While the whole subject is as complicated as one wants to make it, I would be very surprised to see a modern motor (say the last 30-40 years) display the output power as opposed to the input power requirements.

All this "true HP" malarkey is irrelevant when rating the supply to a machine. It doesn't matter if the machine is a poor 10% efficient. If it says it's a 10A machine, it should never draw more than that (startup excluded). Whether it cuts well is an entirely different story, however.

Mark, motor power ratings are output power, if you have a motor rated 3Kw/4HP that's what you get out of the motor.

What power you put into it is determined by the motor efficiency, and what current you have to supply to it is governed by the efficiency and the power factor.

The manufacturer will state the output power in HP in the US, in Kw elsewhere, and the motor rated input current.

Motor input power isn't usually stated on the nameplate, although if the efficiency is stated you can calculate the input power.

Regards, Rod.

[Peter Franklin]

Hi all,

I have a similar question to the original poster. Want to buy and run the GO513x2 on a 110v 20amp line but tech support is telling me I need 30amps.

I read through the thread, and even if we assume 1 HP = 1000 watts, the formula (P=I x V, I=P/V. I=2000/120. I=16.66A) indicates 20 amps would be more than enough.

So why is Grizzly tech support saying otherwise? Are they just being overly cautious to avoid lawsuits or something cause it's close to the threshold, or am I going to run into problems?

Thanks,

Peter

[Dave MacArthur]

Sizing Wires and circuit breakers for 3HP and 5HP shop motor circuits (http://www.sawmillcreek.org/showthread.php?153271-Sizing-Wires-and-circuit-breakers-for-3HP-and-5HP-shop-motor-circuits)

Need to read the thread above to get your answer. 12 ga 20A is plenty to run a 2HP motor, and your saw will run just fine on that. So why is there a disparity in the manual vs. the specs? Because while the motor will draw at max the nameplate amperage at 115V, the NEC does not actually allow you to run a motor branch circuit that way.
--Must size circuit for 125% of Full Load Current (FLC) which is not from the nameplate but MUST come from a table in the NEC, in this case it is 24A. Must use "continuous duty" motor sizing in this case and size the circuit at 125% of 24A, so that = 30A.
--From the table 310-16, using the 75C column for wire termination criteria, I need 10ga wire to remain below 75C while pulling 30A. If I use NM cable, I have to use the 60C column, and 10ga NM wire will stay at or below 60C running 30A, so it's still fine.
--From same table, for current through the wire, I am allowed to use the 90C table if using THHN or NM wire, and you can see 12 ga will flow 30A and stay below 90C. Unless I have to derate for cable bundling of more than 3 conductors in some conduit, or greater than 86F temperatures around the wire, then I'd have to derate and 12ga will NOT flow 30A and remain below 90C, and I'd have to step up to 10ga for this answer.
--In any case, I must use the larger gauge wire from either of the above two criteria for determining wire size on a motor circuit, and that means 10ga.
--Final check is to FINALLY look at REAL, EXPECTED amps from the nameplate and just sanity check that it will flow fine through the determined 10ga wire, and indeed the 20A from the nameplate will.

So, THAT is why they say 20A is the motor draw, but you must use a 30A circuit if running 115v--because the NEC says you have to, and the NEC allows motor and circuit breaker manufacturers to EXPECT and engineer heat dissipation assuming that you will follow the NEC and provide these beefy conductors to motors. The 10ga 30A circuit, while not required for actual amps drawn on the saw, IS required for NEC allowed motor heat dissipation--the conductor is used to dump motor heat, and 10ga/30A is required to keep the wire from approaching the boiling point of water and to stay below 75C or 167F (smoking hot!), thus not damaging your circuit breakers.

Read my thread up above for more info, no one ever believes the correct answers so this subject comes up again and again. Just remember, the wire sizing for motor circuits is not primarily based on the motors current draw, but instead on creating a heat sink to dissipate possible heat from a worst case scenario that the NEC requires you to use.

However, I'd just rewire it to 230V and leave it on a 20A/12ga circuit. ;)

[Peter Franklin]

Hey Dave,

Thanks for all the info. Read through it and I must admit it went straight over my not-so-technically-wired head.

So here's another related question. If I able to run this machine on a 20amp circuit without it tripping the breaker, am I putting a greater strain on the motor and potentially damaging it?

I could upgrade the existing wiring but an electrician quoted me $250-$350 for upgrading to 30amp and $750 for upgrading to 220 (I live in NYC). Would prefer to avoid those costs... but don't want to break the machine by doing so.

Thanks again.

[Keith Hankins]

I've got the G0513. At the time they did not have the X2. The only diff is the type of wheels and trunions so the motor is the same. My 2hp has always called for the 20A and Never had an issue. However, I'm a firm beleiver that you should go with the reccomendations. If you decide to go with the 20A because thats what you have then if it trips change imediately.

[glenn bradley]

Just a contribution from an experience I had. I bought a hybrid tablesaw because I didn't have 240v and didn't know enough about re-wiring to know how basic it is. Within a few months I had a G0513X and was adding 240v outlets. The reason I toss this out there is to help others not make poor decisions based on shop circumstances that can be easily changed. Enjoy.

[Dave MacArthur]

So here's another related question. If I able to run this machine on a 20amp circuit without it tripping the breaker, am I putting a greater strain on the motor and potentially damaging it?

No, you're not. The motor has it's own thermal overload protection that is actually what protects the wire/circuit; the CB on a motor circuit (with motor overload on the motor) protects from ground faults and shorts.

This is actually a personal risk decision. Yes, the saw will run fine on your 20A circuit. Yes, the NEC would spec 30A if you were getting it put in as a permanently connected device and the electrician ran it that way. Yes, the NEC is way conservative there and the spec, though required to be followed for permitting etc., does assume you are running the motor continuously (>3 hours), at full load current (cutting a 3 mile long board of 12" high Ipe or hard maple with a stock feeder blazing the board into the blade at max feed rate...thus demanding full current). No, you're not going to ever use the saw in anything remotely resembling that current-draw and temperature-rise scenario. Yes, running your saw on 12ga 20A circuit will likely never trip the breaker and won't damage the saw, and probably won't make your wires get hot enough from current draw to damage the motor connections or the circuit breaker, nor burn your house down...probably.

Make your own call here, and accept the results--it's a pretty low risk. The speed limit is 55, your wife's in the car having a baby--you pick the speed. You've got a 20A circuit, your saw says... ;)

[ken gibbs]

I have the GO555x with the riser block. I use a Woodslicer 1/2 blade and it resaws nicely as well. No complaints about the saw or the blade. Timberwolf blades are a different matter. I have a 3/4 inch that I'd be happy to send to anyone who wants it. It does not work on my saw.
Regards,
Tom

Tom, I have a one year old Grizzley G0555X and want to upgrade to a good resaw blade. I don't have riser blocks for this saw. Do I need to buy cool blocks and install them befre buying a 93 1/2" Woodslicer blade for my saw? thanks.

[Paul Johnstone]

Both have a disagreement between catalog specs (20A/110v) and manual requirements (30A/110v). I called Grizzly technical support and was told that the specs had changed and 30 amps are required. I confirmed the change was in the specs, not the saw, making me wonder if there's a whole bunch of 513 and 457 owners happily using with 20A circuits, oblivious to the paperwork.
.

Maybe this is a dumb response, but if Griz suddenly changed the specs to say that you need a 30 Amp circuit, I would tend to do what they said. They aren't going to change that spec for no reason, as it is going to be a major inconvience for most people. I'm guessing you can wire the motor for 220V and put in a 220V, 20 amp circuit. That's what I would do if I was buying the tool. (In general, if you go to 220V, you need only about 1/2 the amps). Plus, the 220V circuit would potentially be more useful for other tools.

Maybe it needs the extra amps on startup? From what little I know, some motors require a lot of amps to get started, but then once they are running, they use less.

I have a Rikon BS (the 18" one though) and totally love it.