Current draw of planers with Shelix cutterheads

[Anthony Whitesell]

I have changed the cutterhead of my Jet JWP-15CS from the straightblade to the Shelix. Now I am tripping the overload of the planer. I have a Centech clamp on planer and it reads 9A when idle and 17-19A when running 8-10 wide boards taking a 1/16" cut. I wish I knew what it drew prior to the change, even with old blades. The faceplate on the motor lists the FLA at 14. I'm surprised the no load current is 9A of the 14 FLA. Is that what is typically seen? The lowest range of the clamp on meter is 200A (:() How accurate do you think the Centech clamp on amp meter is?

[Richard Coers]

I thought it was common knowledge that carbide insert heads take more horsepower than straight blades.

[Anthony Whitesell]

That wording never appeared in my research. Current yes. HP no. In my research, those that measured and provided the differential never had numbers higher than the rating for the machine or the motor. Yes the currennt measurements were higher than the straightblade but not beyond those of the machine (in the case of the converted lunchbox planers) or the FLA of the motors for those that provided data for a floor standing planer.

The two things that I'm focused on are the 9 amps idle current. Ie., cutting nothing and it draws 9 amps. That seems high to me. Then the 2x increase in current (which goes above and beyond the FLA) when taking a measly 1/16" cut. I wish I could compare to the 12 1/2" Delta straight blade lunch box planer I had previously. All it could do was 1/16" cuts. A 1/8" cut was out of the question for the Delta lunch box planer.

[Richard Coers]

An 1/8" cut is out of the question for nearly every lunch box, and many have issues taking 1/16" at full width.

[Kevin Jenness]

That looks like a pretty common Asian planer design. Perhaps you can find one in your area, whether Jet or another brand, and test it. It's interesting to note that a comparable model with a "3hp" motor lists FLA as 11 amps (p.6) https://go.rockler.com/tech/60724_instr.pdf Is there room to replace the motor with a 5hp?

[Anthony Whitesell]

My Delta had an "internal" or inheirent (?) depth stop that limited it to 1/16". I never had a problem taking a 12" x 1/16" cut other than the zillion passes it take to turn rough cut into finished lumber. But that is past. Now I need to figure if I just wasted $800 on a shelix head or if there is something I should be looking for within the planer that would explain the high current readings.

[Anthony Whitesell]

That looks like a pretty common Asian planer design. Perhaps you can find one in your area, whether Jet or another brand, and test it. It's interesting to note that a comparable model with a "3hp" motor lists FLA as 11 amps (p.6) https://go.rockler.com/tech/60724_instr.pdf Is there room to replace the motor with a 5hp?
It is a closed stand version, with the motor mounted below. So I believe there would be room. Can you run a 5HP motor from a 220V 20A service? The Jet 3HP motor faceplate states 14FLA. A quick search of 3HP motors did not turn up anything with as high a FLA, as you ellude. Perhaps Jet did not use a very efficient motor and another 3HP motor would not have the same current draws.

[Greg Parrish]

It is a closed stand version, with the motor mounted below. So I believe there would be room. Can you run a 5HP motor from a 220V 20A service? The Jet 3HP motor faceplate states 14FLA. A quick search of 3HP motors did not turn up anything with as high a FLA, as you ellude. Perhaps Jet did not use a very efficient motor and another 3HP motor would not have the same current draws.

If it’s a true 5hp, you are going to need a 30 amp circuit (and wire capacity) most likely. I know my prior Minimax 16 saw with 4.8hp required the 30amp. That said, I know some folks ran/run their Minimax bandsaws on 20 amp, but it truly calls for a 30 amp circuit.

On my DW735 planer, when switching from straight to Shelix, it pulled more amperage on the line. I learned this one day because I was running it on an extension cord that had a built in 15amp circuit breaker and with the Shelix it would trip. When moving to a 20amp circuit with 12 ga cord without the little breaker, it ran fine. I didn’t bother putting a meter on the line but it for sure wouldn’t run on the 15 amp circuit any more when the bite size got to big or wood type got too hard.

I’m betting the motor efficiency could be an issue, but seems like I read somewhere about having to take smaller bites on the Shelix heads. Maybe you need to drop down to 1/16” max passes. Sorry I can’t be of more help, but I do think you are seeing a normal phenomenon with regards to the Shelix needing more power.

[James Jayko]

If you can replace the cutter head, you can definitely add a 20A circuit...

[Greg Parrish]

If you can replace the cutter head, you can definitely add a 20A circuit...

Not sure if that was directed at me, but I have a shop full of 20amp circuits, along with multiple 220v 20amp circuits. My issue was an inline 15amp breaker installed on the 12ga extension cord by the manufacturer. Using a different cord without it and mine works fine.

With regards to the OP, his planner appears to be a 220v 3hp motor that is tripping a 20amp circuit now if I'm understanding correctly.

[Bill Dufour]

That wording never appeared in my research. Current yes. HP no.
You just did not understand that horsepower is just current times voltage. The voltage should stay constant or very little drop in a normal house with no extension cords. So double the current is double the horsepower.
The calculator below says you are making 6.1 Hp if the motor was 100% efficient. My pool pump motor is about 60%. efficient. So 60% x 6.1= 3.6 hp
one horsepower is 746 watts so input horsepower is (amps x volts) / 746
Bill D.

https://www.inchcalculator.com/amps-to-horsepower-calculator/

[Ken Combs]

Can I assume you have the clamp on meter around 1 conductor, not two? If so, I'd suspect the meter accuracy.

[Anthony Whitesell]

With regards to the OP, his planner appears to be a 220v 3hp motor that is tripping a 20amp circuit now if I'm understanding correctly.
Close. I have only 20A outlets and distribution breakers servicing my shop. It is not the 20A distribution breaker that is tripping. The 15A motor overload in the control box on the machine is tripping.

Edit: Next morning thoughts. I'm finding it interesting that the FLA is 14A and the overload is set to 15A. IIRC, there is a 125% rule in the NEC where the overload can be (should be?) 125% of the FLA, in this case set to 17-18A.

[Anthony Whitesell]

You just did not understand that horsepower is just current times voltage. The voltage should stay constant or very little drop in a normal house with no extension cords. So double the current is double the horsepower.
The calculator below says you are making 6.1 Hp if the motor was 100% efficient. My pool pump motor is about 60%. efficient. So 60% x 6.1= 3.6 hp
one horsepower is 746 watts so input horsepower is (amps x volts) / 746
Bill D.

https://www.inchcalculator.com/amps-to-horsepower-calculator/
I am well aware of the math applied to convert volts, amps, power, and horsepower. Using the faceplate to determine HP is a common folly. Based on the faceplate of this motor, it would be 73% efficient. 14FLA, 220V, 73% = 3HP. What about a 3HP motor that has a FLA of 11A on 220V? That means the motor is 93% efficient? So I should install this 11A 220V motor in the planer? The math extrapolates that if 14FLA, 220V, 73% is 3HP, then when the motor draws 19A then the 3HP motor is producing 4HP. Which is not possible. Therein lies the folly of using the math to determine (or even speak of) horsepower.

[Bill Dufour]

A decent electyric motor is designed for max efficiency at its stated FLA. It can go above or below that for more or less horsepower. But those amps are usually less efficient. Going below is usually not a problem as long as rpm stays high enough for cooling. Going above FLA will cause overheating. Not a good thing for long time periods. Duty cycle must be considered.
Bill D.

[Keegan Shields]

What style of breaker is tripping? Those small button style breakers are notoriously unreliable. You might consider installing a replacement to see if that’s the issue.

[Curt Harms]

My Delta had an "internal" or inheirent (?) depth stop that limited it to 1/16". I never had a problem taking a 12" x 1/16" cut other than the zillion passes it take to turn rough cut into finished lumber. But that is past. Now I need to figure if I just wasted $800 on a shelix head or if there is something I should be looking for within the planer that would explain the high current readings.

From memory (but I'm pretty sure about it) Jet's JJP-12 straight knife machine's planer feed rate is 20 ft./min. The JJP-12 HH planer feed rate is 12 ft./min., the additional power required by the helical head is why. It is possible to replace a part/parts on the JJP-12 to slow the feed rate to that of the JJP-12HH, I don't know if it would be practical to change parts on the drive train of your machine.

[Kevin Jenness]

If your current measurement is correct, then the internal motor overload may be tripping properly. Could be just too much strain with the new cutterhead, in which case a slower feed speed as Curt suggested may be in order, or a more powerful motor, or perhaps there's a problem which a motor shop could diagnose. It's also possible that the internal breaker is bad. You could try replacing it or jumping past it and monitoring the motor for heat buildup.

[Anthony Whitesell]

Can I assume you have the clamp on meter around 1 conductor, not two? If so, I'd suspect the meter accuracy.A clamp meter will only read if it is around one wire. The measurement around 120V L and N or 240 H1 and H2 is 0A, +A in L or H1 and -A in N or H2. +A-A=0.

[Anthony Whitesell]

What style of breaker is tripping? Those small button style breakers are notoriously unreliable. You might consider installing a replacement to see if that’s the issue.
Motor overload in the control box. I would need to re-disassemble the box to find the manuacturer.

It is something similar to
https://www.rockwellautomation.com/en-us/products/hardware/allen-bradley/circuit-and-load-protection/motor-protectors--low-voltage/overload-relays--solid-state/193-iec-e1-plus-relays.html

[Rod Sheridan]

I am well aware of the math applied to convert volts, amps, power, and horsepower. Using the faceplate to determine HP is a common folly. Based on the faceplate of this motor, it would be 73% efficient. 14FLA, 220V, 73% = 3HP. What about a 3HP motor that has a FLA of 11A on 220V? That means the motor is 93% efficient? So I should install this 11A 220V motor in the planer? The math extrapolates that if 14FLA, 220V, 73% is 3HP, then when the motor draws 19A then the 3HP motor is producing 4HP. Which is not possible. Therein lies the folly of using the math to determine (or even speak of) horsepower.

Actually there is absolutely no issue with the 3 HP motor producing 4HP, except for the fact that if it does it continuously it will burn out.

That’s why motors require overload protection.

The motor is overloaded due to a less efficient cutter design. This is a known characteristic of some insert heads.

Regards, Rod

[Ken Combs]

A clamp meter will only read if it is around one wire. The measurement around 120V L and N or 240 H1 and H2 is 0A, +A in L or H1 and -A in N or H2. +A-A=0.

Yep, I was thinking of my 240/3ph and the strange readings if around the 208 and one of the others!

[Carl Beckett]

Not sure if it helps, but the motor overload protection may be a thermal switch (temperature triggered). Whereas breakers are current triggered (which may still be a thermal effect, but designed to trip at a max current level).

I have read (and seen youtube video) that Shelix heads DO draw more current than straight knives (on the Dewalt 735)

Without having the comparison values it is hard to know if binding/alignment issues after disassembly.

I dont know the accuracy of your meter. If 1% of full scale, that would be +/- 2amps. And you may be trying to read more accurately than that so again hard to say.

Fact is, it is tripping. And it sounds like it 'might' be due to a higher load due to the change in head. If that breaker is part of the machine, there might not be much to be done without deviating from the manufacturers design limitations (which then becomes a safety risk).

[Carl Beckett]

Can you run a 5HP motor from a 220V 20A service?

No, requires a 30A (if pulling full rated power).

[Anthony Whitesell]

I dont know the accuracy of your meter. If 1% of full scale, that would be +/- 2amps. And you may be trying to read more accurately than that so again hard to say.
You detailed what was vauely in my head. Thanks.


Without having the comparison values it is hard to know if binding/alignment issues after disassembly.
Also an item I was considering since the head was very difficult to remove and reinstall. I'm going to pull the infeed and outfeed rollers and see what the current reads with only the cutter head spinning. More than that means disassembling the gearbox, again, and another $30 bottle of gear oil.

[Michael Burnside]

No, requires a 30A (if pulling full rated power).

Correct. A 5HP motor, 240V, single phase with 100% efficiency is a little over 15A. That is idealistic, not going to happen or will happen with very little wiggle room. If you push that number down to 80% efficiency then you're right at 20A, which means you really should be running from a 30A service.

[Anthony Whitesell]

No worries. I have a 3HP 220V 11A motor on order. That will give me more overhead before I hit the current overload (set at 15A).