Porter Cable Biscuit Jointer 557 Only 7.0 Amps -- Not 7.5 Amps as Advertised

[John Urban]

This isn't a HUGE deal, but I just got a new Porter Cable 557 Biscuit Joiner Type 4.

It was advertised as 7.5 Amps and the shipping slipped from the manufacturer (it shipped directly from B&D in Jackson, TN) said 7.5 amp biscuit joiner, BUT the information plate on the tool says 7.0 amps. I know... I know... It isn't even 10% less power, but it is still not what was advertised and something lesser than prior models.

Of course, it feels super shady to a guy who just bought a new tool... The type 3 models, that were also made in Mexico, were 7.5 amps (just check out the product pictures at Amazon.com if you don't believe me). So, that likely means the type 4 models fell victim to the root of all evil -- cost reduction -- and a lesser motor was used.

If you happen to be in the "know" on the details behind this change, I'm curious and would like to hear about it.

Thanks for listening... just wanted to rant.

[Ken Fitzgerald]

John,

At the PC website http://www.deltaportercable.com/Prod...roductID=11115

It shows it as 7.0 amps......not 7.5 amps....

[Mike Henderson]

Unless you find that the motor drags or stalls when using it, the amperage doesn't matter. The motor is powerful enough to do the job.

In any case, even if your motor uses less amps, it could indicate that a more efficient motor was used, not that a less powerful motor was used. It's fairly easy to use more amps by wasting some of the power if you just want to show more amp usage. It's tough to reduce losses and produce a more efficient motor.

Mike

[Todd Franks]

So, that likely means the type 4 models fell victim to the root of all evil -- cost reduction -- and a lesser motor was used.

If you happen to be in the "know" on the details behind this change, I'm curious and would like to hear about it.

To play devils advocate, there is another possibility. A better motor with higher efficiency was used on the type 4, thus the lower ampere rating. I don't know the details, but I would assume your suspicion is more likely. Even if a lesser motor is used on the type 4, I doubt you'd notice the small difference. I've never had any issues making plunge cuts with my type 2 PC557 in material as hard white oak or maple. It's a nifty little machine when you need it. Enjoy.

-Todd

[Paul Ryan]

As other have posted it may have a more efficent motor. As much as tool manufacturers want us to believe it Amps is not a measure of power produced. It is just a measure of current draw. To really no how much power your tool is putting out you need to know the watts. A motor that draws 10 amps, and one that draws 7 amps may produce the same amount of watts(power), but the second motor is more efficent.

[Jerome Hanby]

With what they've done to the Porter Cable product line, my vote would be cheaper no better...

But, considering what the tools does, I bet it makes no practical difference when it come to using it.

[Steve Kohn]

It could be something as simple as the tolerance in the specification of the motors.

[Jay Jeffery]

With what they've done to the Porter Cable product line, my vote would be cheaper no better...

That would be my guess. Since BD bought PC in 2004, the line does seem to be going down hill. Again, just a guess.

I think it very unlikely that they can deliver a power tool motor with equal or greater power with lower consumption in a tool in this price range. We can acknowledge the possibility, though. Sure.

[Terry Welty]

I'll trade you even up for my Harbor Freight unit...

[Keith Weber]

...Amps is not a measure of power produced. It is just a measure of current draw. To really no how much power your tool is putting out you need to know the watts. A motor that draws 10 amps, and one that draws 7 amps may produce the same amount of watts(power), but the second motor is more efficent.

OK, I thought that

Watts = Amps x Volts

So, for a given voltage (which shouldn't change if you're plugging into the same outlet), the watts and amps should be relative. How can you go from 10A to 7A without affecting the Watts? The above formula is quite common. I am open to enlightenment.

Keith

[Neil Brooks]

You have it right.

The efficiency of the motor would be a measure of work out vs. power in.

Work out can be measured as HP (can be expressed in watts) or torque (can be converted to HP).

Power in can be measured as watts drawn.

Watts IS equal to amps * volts.

[Neil Brooks]

Incidentally .... numbers on ads, websites, and product badges notwithstanding ... how's it WORK?

I'm in the market for a biscuit joiner, and have been considering the 557. Seems to have a GREAT reputation.

[Ken Fitzgerald]

Keith,

Paul will tell you he and I seldom agree on anything.....but both he and Neil are correct on this one.

All motors are not designed and built equally.

The 7.0 amp motor could be a more efficient motor and therefore actually produce more horsepower at it's output. Thus a given blade on the 7.0 amp motor might cut much more efficiently.

[Charlie Plesums]

OK, I thought that

Watts = Amps x Volts

...

...

Power in can be measured as watts drawn.

Watts IS equal to amps * volts.

Okay, if you want to be technical, both are wrong. Watts does equal volts times amps for direct current. For alternating current, you need to start with RMS measure, which is a funky averaging to make it comparable to direct current if the voltage and current are in perfect synch.

For AC, power (watts) is RMS voltage, times current (amps) times the power factor. The power factor is the cosine of the angle between the sine wave voltage and the sine wave of the current. If they are in synch, the power factor is cosine(0)=1, but motors have coils, which is an inductive load which makes the current lag the voltage changes.

Then we get into the efficiency. Does your motor get warm? Does it make noise? Does it blow air? The input power has to provide the heat and noise, in addition to the useful work of spinning the blade.

Okay, so what does all this pompous info mean? I bet you won't be able to see the difference between a 7 amp and a 7.5 amp tool. And the difference may have been as simple as a different guy doing the testing in a different lab.

[Paul Atkins]

If you want more amps, just short out the line leads with a piece of #8 copper. It will give you all the amps you can handle - for a second. (O.K., don't really do that.)