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Forum topic by bbasiaga posted 03-02-2017 05:28 PM 356 views 0 times favorited 7 replies Add to Favorites Watch
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bbasiaga

1011 posts in 1834 days


03-02-2017 05:28 PM

I have what I hope does not turn out to be a dumb question. All handheld routers are 110v in the US, at least that I know of. But some are sold as 1.5hp, 2.5hp, 3.25hp…

We know that a 20amp 110v circuit tops out at about the 1.5hp mark, so what is the real difference between these routers? I am gone it must just be the amount t of torque the motor turns out, allowing it to run bigger bits. Thoughts?

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.


7 replies so far

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Madmark2

373 posts in 427 days


#1 posted 03-02-2017 05:37 PM

Router power figures are inflated like the wonderbra. Torque is what counts.

Big (3+ hp) routers need variable speed to slow down for large diameter cutters. Small routers (~1 hp) tend to run full tilt all the time.

Big routers live in tables, small and medium routers you can free hand.

You’ll spend more on bits than routers.

M

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TheFridge

8333 posts in 1325 days


#2 posted 03-02-2017 05:38 PM

It does for an induction motor but universal motors are measured differently.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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Rrrandy

212 posts in 318 days


#3 posted 03-02-2017 05:45 PM

http://www.rapidtables.com/convert/power/how-watt-to-hp.htm

Watts=current * voltage

1 watt = .00134 hp

-- Y'all need to locate a sense of humor. Borrow one if you can't find yours...

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bigblockyeti

4698 posts in 1560 days


#4 posted 03-02-2017 06:16 PM

You will almost all of the time get more torque out of a universal motor that is larger in diameter due to the longer effective torque arm from the center of the shaft to the OD of the armature. There is no fixed motor OD to armature OD ratio that every manufacturer is going to exactly follow so that coupled with countless other variables can make a direct comparison difficult. I have noticed that many of the 3+ HP routers are more likely to have a maximum speed at or under 25K rpm whereas those at 2 1/4 HP or less tend to be over 25k rpm. This makes sense as few people weould want to hold a 3 1/4 HP router while running a 1/4” radius round over bit through soft wood, it would not only be extreme overkill but quite fatiguing as well.

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Rich

1985 posts in 429 days


#5 posted 03-02-2017 10:32 PM

They generally do those tests using measurements of start-up current, or for a lock-rotor measurement, where the current is high. The tests only last a second or so. That’s how 12 amp motors get rated at 2-1/4 hp and higher. The inrush current is higher that 12A, so they use that for the horsepower calculation. I’ve seen 15A motors that were “rated” at 5 hp on the adhesive label stuck to the front of the machine in the store.

-- No matter how much you push the envelope, it'll still be stationery.

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MrUnix

6015 posts in 2038 days


#6 posted 03-02-2017 11:30 PM

I’ve seen 15A motors that were “rated” at 5 hp on the adhesive label stuck to the front of the machine in the store.
- RichTaylor

Like my “5.5HP” shop vac that runs on a standard 15A 120v wall outlet :) It’s gotta be true, as it’s printed right there on the front of the thing in big bold letters!

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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Mikenln

13 posts in 612 days


#7 posted 03-02-2017 11:38 PM

The horsepower of a router is determined by the marketing department. The engineering department determines the amps.

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