Old 2 hp vs. new 3 hp.

[Josh Reid]

Would an older 2 h.p. unisaw have similar power to the new 3 h.p. versions?

[Neil Brooks]

In theory, I'd have to say no.

The newer motor may well be more efficient, but that only means that -- for each horsepower generated -- all things being equal -- it draws fewer watts.

But 3HP should -- in theory -- still be 50% more than 2HP.

Good place to look at this kind of thing ....

http://www.elec-toolbox.com/Formulas/Motor/mtrform.htm

[Rod Sheridan]

No, a 3HP motor has 50% more output power than a 2 HP motor.

The HP hasn't been re-defined.

The new motor may have higher efficiency and better power factor as well.

Regards, Rod.

[Phil Thien]

I've used a Unisaw with a 1.5-HP bullet motor that way out-muscled an imported hybrid saw with 1.5-HP motor.

[ken carroll]

I've used a Unisaw with a 1.5-HP bullet motor that way out-muscled an imported hybrid saw with 1.5-HP motor.
Ah yes, but that's not old HP vs New HP, that is real HP vs Chinese HP.

[Josiah Bartlett]

As an owner of an old 2hp Unisaw, I'd say it won't outdo a new 3hp Unisaw, but its still a great saw and I pretty much never need any more power for the kind of work I'm doing. If I was power feeding 8/4 oak with a dull blade all day I'd probably want it, but I'm just a hobbyist.

[scott spencer]

I've used a Unisaw with a 1.5-HP bullet motor that way out-muscled an imported hybrid saw with 1.5-HP motor.

There are several variables in play besides HP though. Alignment, blade, the supply circuit, belts, pulleys, the material. and torque curves of the motors are just some of the things that could influence our perception of cutting power.

[JohnT Fitzgerald]

There are several variables in play besides HP though. Alignment, blade, the supply circuit, belts, pulleys, the material. and torque curves of the motors are just some of the things that could influence our perception of cutting power.

Very true. However, some time ago, companies started to play the "HP" game, using "Peak HP" that is derived from the maximum inrush current @ startup time. 1.5 peak HP is very different from 1.5 continuous HP.

I would hazard a guess that the 3HP uni is truly 3HP; and that the 1.5HP "import" mentioned above was using a questionable rating...

[Curt Harms]

I'm pretty sure those "horsepower games" were played with universal motors. Most stationary machines use induction motors without the "Sears enhancements". Yeah, I know other mfgrs. do the same thing but Sears was the pioneer AFAIK.

[scott spencer]

I'm pretty sure those "horsepower games" were played with universal motors. Most stationary machines use induction motors without the "Sears enhancements". Yeah, I know other mfgrs. do the same thing but Sears was the pioneer AFAIK.

They tried playing the games with the induction motors for a while too. I've seen several of the older Cman contractor saws that state 3hp right on the front, but plug into a standard 110v outlet...I don't think they've had any recent induction motor saws that play the game anymore, but more recently Hitachi played that game with their "3hp" C10FL...the motor plate states 15 amp 1.5hp. :rolleyes: A lawsuit against compressor companies for overstating the HP seemed to cut down on that activity, but the games continue like crazy with the universal motors....I've got a 6.25hp Ridgid shop vac that plugs into a standard 110v outlet!

[Bill Orbine]

They tried playing the games with the induction motors for a while too. I've seen several of the older Cman contractor saws that state 3hp right on the front, but plug into a standard 110v outlet...I don't think they've had any recent induction motor saws that play the game anymore, but more recently Hitachi played that game with their "3hp" C10FL...the motor plate states 15 amp 1.5hp. :rolleyes: A lawsuit against compressor companies for overstating the HP seemed to cut down on that activity, but the games continue like crazy with the universal motors....I've got a 6.25hp Ridgid shop vac that plugs into a standard 110v outlet!

That's it...... you need to look at the motor tags for the HP and amp ratings more importantly than the on the box "Peak HP" rating. I pay more attention to the amp draws rather than the HP ratings. Today, it's said one hp on 115 volts is expected to be somewhere around 9-13 amps depending on the motor and it's application. Older motors do have higher amps onthe motor plate. I've got an old 20" bandsaw with a 1hp motor on 115 volts and it's 15 amps. It starts right up to full speed quickly.

[Rod Sheridan]

That's it...... you need to look at the motor tags for the HP and amp ratings more importantly than the on the box "Peak HP" rating. I pay more attention to the amp draws rather than the HP ratings. Today, it's said one hp on 115 volts is expected to be somewhere around 9-13 amps depending on the motor and it's application. Older motors do have higher amps onthe motor plate. I've got an old 20" bandsaw with a 1hp motor on 115 volts and it's 15 amps. It starts right up to full speed quickly.

It is important to check the motor nameplate for HP ratings, however motor current can be misleading.

A poor motor will have higher current ratings for the same HP compared to a high grade motor.

A high grade motor will have higher efficiency and power factor, resulting in lower input current and power compared to a lower grade motor.

Regards, Rod