Startrite bandsaw replacement motor

[Carl long]

Hi All

I have the possibility of getting a Startrite 14-S-5 bandsaw. Like a lot of these machines it's a 3 phase one. It won't cost me anything other than the sweat and tears it takes to move the 318kg weight. I have a replacement motor in mind that again is free. The motor comes from a DeWalt Dw3401. I can't find a motor rating for the Startrite (can't find it in the manual & motor has no plate on it.) The 352 a later model with the same throat and cutting height has a 1.5hp motor. The Dw3401 has a 1hp motor. The DeWalt was a lighter machine with a smaller depth of cut at 6". Do you think I'm going to miss that half horsepower. I don't resaw 10" oak boards I mainly want it for the extra throat. Will it harm normal everyday performance?

 

[mrpercysnodgrass]

Your post prompted me to look at the motor on my 14s-5 something I have never done all the time I have owned it. It turns out my one has a replacement 1hp motor. I mostly cut small pieces of timber but occasionally large logs and 8" lumps of oak. It has never struggled to cut anything I have put through it especially with a sharp Tuff Saw blade on it.

 

[Inspector]

I would leave the motor ini t and get a Variable Frequency Drive (VFD) to convert your single phase power to three phase variable speed. That would let you slow it down for occasional metal cutting. They seem to average around 60 pounds on your eBay. I know it isn't free but it keeps the full resew capabilities and the machine remains original if you ever want to sell it.

Pete

 

[Carl long]

Thanks for your replies. Lots to think about. Good to know others have used a similar motor. I had no idea VFD's had got so cheap. The wiring scares me a bit. Fashioning an adaptor plate is right up my luddite street. However there are lots of threads on using a VFD. Even with a short search it appears I have to rewire the motor from star to delta. It might not cost me anything selling the DeWalt might pay for the VFD. How good are these cheap Chinese VFD's. Can anyone recommend a model?

 

[worn thumbs]

I wouldn't get too excited by the thought of slowing the machine to cut aluminium.The S5 will probably have a slow enough speed from the stepped pulleys for almost every use.In fact when I used to share a workshop with a 24 T 10 we didn't change the speed between cutting wood or aluminium.

A bandsaw shouldn't need huge amounts of power and 1 Hp would probably be sufficient.I used to know a fellow who used a 3/4 Hp on his own saw and never seemed short of power.Having said that,my own 18 S 5 has a motor which may not be original and which blows 13 amp fuses every few months-I haven't investigated the output of it in the 26 years it has been in the shed.

 

[Inspector]

I bought one from a company called DaiLian PowTran Technology through Alibaba. Some of the Aussies buy direct and that is how I'd do it again. Mine is for my dust collector and is the same one the Aussies put on their ClearVue cyclones to get them up to the same speeds as our 60 cycle power. Gives 20% more flow than 50 cycle does. Contact them and tell them about the motor and application and see what they recommend.

Pete

With the right blade a slowed band saw can cut steel. Keep in mind the swarf can imbed itself in the tires.

 

[Stickler]

I have this exact same model of bandsaw.
When I got it I used it with a VFD and it was excellent.

But when I found I wasn't using it that much I used the VFD on another machine, and changed the 3-phase motor on the bandsaw for a single phase motor. It was a straightforward job to change it but I much preferred the machine with its original 3-phase motor; much smoother and quieter.

Also remember with a vfd you can program in soft-start and electric brake.

 

[Jacob]

Drop from 1.5 to 1HP will slow cutting feed speed down. It's obvious really, otherwise what would be the point of a bigger motor.

 

[Inspector]

Be big man! Har. Aar. Grunt! (hammer)

Pete

 

[sunnybob]

Drop from 1.5 to 1HP will slow cutting feed speed down. It's obvious really, otherwise what would be the point of a bigger motor.

At the risk of starting yet another irate thread//// :shock: :shock:
Jacob, youre slightly wrong.

A motor is rated two ways, HP, and torque.
HP (Horse Power) decides how fast the motor goes, yes, to a degree. BUT, the top rated speed of the motor in question is the deciding factor.
A large horse power motor can often be rated at a slower speed than a lower horsepower motor depending on the application required.

Its not difficult to get a low HP motor to spin faster than a high HP motor.
But heres where the second measurement "Torque" comes in.
Torque decides how quickly the motor gets to speed.
If you feed a piece of wood too fast through a low torque motor, it will slow down and even stop, regardless of the free wheeling speed.
If you feed a piece of wood too fast through a high torque motor, the blade will bend and then snap, regardless of the freewheeling speed.
HP and torque cant be seperated.

 

[Eric The Viking]

All other things being equal, Jacob is quite right.

Bob, I think you are somewhat muddled, or at least your post seems to be:

Each blade tooth is a tiny chisel. Imagine they are sharp; taking a bigger cut needs more force (= power) than a smaller one. The depth of cut is determined by your feed speed, so a more powerful motor lets you feed faster (for any given height of cut).

For completeness, say you have a smaller motor but turning faster: it will stall more easily, so you don't gain anything from the extra speed.

But of course the difference only becomes obvious at the extreme - when you want max power from the motor. Below that limit you can't notice any difference, as either motor can instantaneously deliver what you ask of it.

E.

 

[sunnybob]

Apart from the fact you have used the word "power" where I have used the word "torque, your explanation is the same as mine.

Regardless of teeth, a motor with more torque will cut longer before stalling than a motor with less torque given the same feed rate.

 

[Stickler]

A 1.5kW 4-pole electric motor rotates at 1400 rpm

A 3hp 4-pole electric motor rotates at 1400 rpm

Surely that dictates the cutting speed. In my simple mind only altering the pulleys changes the cutting speed.

 

[Eric The Viking]

In your example, 3 horsepower is roughly 2.2kW, so that motor will tolerate a higher feed rate than the smaller one all other things being equal.

Or in woodworking terms, either would make a given bandsaw function, but when cutting identical stock, the one with the more powerful motor would do it faster. Also, the saw will stall at the point where the cut you are trying to make needs more power than the motor can deliver (kerf, wood type, thickness of stock and feed rate all playing their parts) . The RPM of the motor doesn't matter, but the power of each motor does.

Torque is not power. There's an extra time ("rate of doing") term in the SI dimensions of power, meaning that you could theoretically have either motor geared to produce the same torque, but that still wouldn't mean the smaller one could do as much work in a given time.

In SI units:
Torque = N . M^2 . S^-2 (or joules per radian (of angle) )
Power = N . M^2 . S^-3 (rate of applying torque)
The extra "per second" (power of -3 instead of -2) is the difference.

Sorry about the horrid notation - can't do super- or subscripts on the forum.

E.

 

[sunnybob]

In simple terms (cos thats what I am).
Free wheeling speed (nothing being cut) is decided by the motor speed and the pulleys, regardless of actual motor "power".

What's being discussed is what "slows or stalls" the motor.
Feeding wood very slowly through a low torque motor will allow you to cut even very large pieces (eventually, if you dont die of boredom first)
Feeding wood into the blade at a normal rate, a motor with higher "torque" will cut more before slowing down than a low torque motor.
This force is called Brake Horse Power (BHP) which is NOT the same as Horse Power (HP)