Originally Posted by
Rob Damon
The cost difference between 1 phase and 3 phase are pretty simple to explain in some cases.
If a particular model is available in both 1 phase and 3 phase and the item is evenly purchased between commercial and non-commercial individuals you would expect the same quantity discounts for the motor to apply at the manufacturer's level. (i.e. 100 1 ph motors versus 100 3ph motors.)
If a particular model is available in both 1 phase and 3 phase and the item is mostly purchased by commercial individuals that want the 3 phase version and only a few non-commercial individuals buy it in the 1 phase version, then the manufacturer will be producing a larger number (95% of the machines) of machines with motors as 3 phase and fewer 1 phase motors. (i.e. 10 1 ph motors versus 190 3 ph motors.)
They would get a bigger discount on the larger number of 3 phase motors and maybe no discount on the fewer 1 phase motors. And in fact it maybe a special order each time a 1 phase motor is purchased.
The pure size of the 16" jointer pretty much limits it to someone running a business in a commercial building which has 3 phase electrical service. Yes, there are a few people that are going to buy one for home use, but the majority will be for businesses.
Which means that the majority of the motors for this particular model being purchased are going to be 3 phase which results in a cost savings.
I even asked Powermatic if they could simply replace the 7-1/2hp motor in their 16" jointer with a 1 phase 7-1/2hp motor since they did in fact have a 1 phase 7-1/2hp that was being used in one of their planers at the time. Even as a custom order, they said they would not do it because nobody buys that jointer that does not have 3 phase service and they could not afford to redesign it for one person. I even asked if it would work and I would do the swap out, and they would not respond. I have a 1 phase 7-1/2hp motor on my shop air compressor, so I knew these motors were readily available in 1 phase at that size.