What size motor is enough for a 12" jointer/planer ?

[Niels J. Larsen]

Hi,

Having posted earlier where I asked for advice about which jointer/planer combo to buy, I've now narrowed down my choice (for the moment at least :D ) to the Hammer A3 31.
It's a 12" jointer/planer combo machine and it is equipped with a 4HP (3.0KW) motor.

So - to the question:

Is this motor enough or should I opt for the 5.5HP (4.0KW) option which is only about $100 more ?

Thanks!
/Niels

[Timo Christ]

I would get the bigger motor. Hammer seems to spec their machines with input power ratings, which isn't very nice IMHO. That means the 3kW input motor only has about 2.2kW (3HP) on the shaft.
You can't get a motor that's "too big"...
Regards
Timo

[John Renzetti]

I would get the bigger motor. Hammer seems to spec their machines with input power ratings, which isn't very nice IMHO. That means the 3kW input motor only has about 2.2kW (3HP) on the shaft.
You can't get a motor that's "too big"...
Regards
Timo

Hi, I have to disagree with Timo about the motor. Having used the A3-31 with the 4hp 1ph motor I can tell you it is plenty powerful. During one test I ran some 12" wide glue ups plus some thick timbers with no problem and it seemed like there was power to spare. If you have 3ph readily available then by all means upgrade to the 5.5hp. Nice to have more reserve power.
take care,
John

[Timo Christ]

John,
i think the machine is only available in three phase in europe, as practically every household has three phase power available (electric kitchen stove is the only appliance which uses it in most homes though).
I didn't mean to say that 2.2kW is inadequate, but more power can't hurt.
Regards,
Timo

[lou sansone]

I would think that 4 hp would be fine. I would assume that this being a "modern" machine it is a belted power transmission that takes a 3600 rpm motor and increases the speed by 1.4 to get the standard 5000 rpm on many of these machines. That will lower the total torque by about 40% so timo seems to be right on this one IRT the drop in shaft power. But for the extra 100 bucks maybe you should just get the larger one. I would assume you are talking about an addtional 5% in cost so big woop-ti-do.

lou

[Ian Barley]

I'm with Timo if you have 3ph. You are spending a good amount on this machine and the extra is not much in proportion to total cost.