Why is my MiniMax FS35 so anemic?

[John TenEyck]

I've had a FS35 (14") J/P for about 10 years now, bought used from the original owner. Soon after I got it the motor wouldn't come up full speed, or maybe it just bogged down. I can't remember for sure. In any case, I took it out and brought it to the best motor shop I know of in the area. It is the original 3 KW motor. They changed both capacitors and I had them changed the bearings while they were at it. They said it was operating as it should when I picked it up.

I reinstalled the motor and it ran fine again. However, before and after the need for service, I can't plane more than 1/32" off on a full width board with bogging down the motor. In the worst case, I've tripped the onboard overload relay, which is set at 17 amps, the full load rating of the motor. That FLA rating seems low for a 3 KW motor, more like what a 3 HP would be rated at. Anyway, I've been considering changing out the 3 knife cutterhead for a Byrd spiral, but that's going to need more power, which makes the proposition a no go.

Here's the conundrum. Most 15" planers have a 3 HP motor and seemingly can handle a full width board at a reasonable depth of cut. Reasonable to me is at least 1/16". If 3 HP lets you cut 15" wide, why can't my 4 HP motor handle 14"?

The new MiniMax FS41 (16") has a 4.8 hp motor, and is the same with either the Tersa or spiral head. Mine is 3 KW, which is 4 HP. Can the FS41 with a segmented head manage 1/16" on a full width board? If so, you would think my 4 hp motor could handle the same DOC with straight knives. I'm confused.

Anyone have some thoughts on this?

John

[Warren Lake]

dont know what your problem is but the SCM combos I have are 3Hp 14" and could take an 1/8" off if wanted.

The general was 3 HP on 14" and 14 FPM if i remember the SCM is 3hp 14" 20 FPM three phase. They have more power than the General did even with a feed rate of 20 fpm so the general had a gear advantage on top. With both machine the same HP the three phase has more power.

Rod or others an electronic guy will tell you where you could be losing power. Jack said 1 HP for 4" I believe that but since I had a power diff between single and three phase maybe that needs to enter into it as well. sure ill be told a HP is HP and it wasnt.

[Richard Coers]

One issue often overlooked is if a key or set screws have come out. You might have a pulley slipping on the shaft. Not the motor pulley shaft since you installed that after the motor work.

[John TenEyck]

One issue often overlooked is if a key or set screws have come out. You might have a pulley slipping on the shaft. Not the motor pulley shaft since you installed that after the motor work.

Thanks Richard. I can't find anything loose.

For Warren, I doubt anyone will argue with you over 3 phase motors vs. 1 phase. 3 phase motors are 150% more powerful than single phase at the same rated HP. So your 3 hp 3 phase motor would be like having a 4.5 hp single phase motor. I doubt an added 0.5 hp, however, explains why your machine can take off 1/8" at 20 fpm when mine can't handle 1/16" at around 16 fpm.

John

[Warren Lake]

is that accurate John? memory past said I was told a HP is a HP and I came to my own disagreement based on observation. Told the roto not as efficient as real three phase power on top.

[Rod Sheridan]

Thanks Richard. I can't find anything loose.

For Warren, I doubt anyone will argue with you over 3 phase motors vs. 1 phase. 3 phase motors are 150% more powerful than single phase at the same rated HP. So your 3 hp 3 phase motor would be like having a 4.5 hp single phase motor. I doubt an added 0.5 hp, however, explains why your machine can take off 1/8" at 20 fpm when mine can't handle 1/16" at around 16 fpm.

John

John, 3 phase motors are exactly the same power output as a single phase motor of the same power rating (Kw or HP).

Your motor would be a capacitor start/capacitor run motor, I would make sure of the following

1) measure the voltage at the planer while planing a board

2) check the start and run capacitors, and verify that there’s current flowing in the run capacitor while the planer is running (clamp on ammeter around one of the run capacitor wires, not both wires)

3) verify the cutter knives are sharp

I normally take 2mm per pass on my A3 which has a 3Kw motor.

I suspect that you have a disconnected or open run capacitor, or low line voltage

Regards, Rod

[Warren Lake]

then why does the SCM have more power than the General did. General 3 HP Leeson brand new 14 FPM SCM 3HP original motor 30 plus years old now close to 60 years old and on a roto so a compromise based on what you have said and higher feed rate so less mechanical gear advantage. doesnt ad up.

[John TenEyck]

From Duke Electric:

What is a three phase motor?


A three phase motor includes an additional wire providing voltage to the system. In the three phase configuration, there are at least 3 wires, and 6 coils placed around the rotor. They are equally spaced 120 degrees apart from each other. This configuration means that three phase motors are able to provide more constant current as the rotor spins. The logic is simple, with a single phase configuration the rotor is only able to deliver current at a single contact point for every 360 degree rotation. In a three phase motor, it is able to deliver current 3 times for every rotation. The result is that three phase motors are 150% more powerful than an equivalent single phase motor.


Maybe it gets down to what the meaning of "equivalent" is.


I'll check #1. I can't check #2 easily at all as the motor is very difficult to access in the cabinet. The knives are sharp; I just resharpened them. 2 mm is 0.080". I can't take more than 1/32" (0.032"). I'll check the line voltage. Typically, it's 240.

Keep in mind, it's always been this way. Before and after I took it to the motor shop. That argues against a capacitor being the problem, unless the run capacitor is the wrong size/rating.

John

[Jim Becker]

I will say that my particular FS350 (same physical cut width but a different generation than your machine) has not really exhibited any issues with power for all the years I've owned it. But full disclosure, I only take about 1/32 or so per pass by personal choice for jointing. It's never been set to any other cut depth since I bought it in 2005. For thicknessing, I typically take no more than 2mm per pass, again by personal choice. For finishing passes, I take less, but keep them enough to avoid roller marking.

[Dan Friedrichs]

The result is that three phase motors are 150% more powerful than an equivalent single phase motor.

John, I know you quoted that from some internet source, but it is absolutely incorrect. A HP is a HP, regardless of how it is generated.

I think the source you quoted was trying to explain one of the very fine nuances of 3 phase power, which is that the net flow of power to a motor does not vary with time (unlike a single phase circuit, where the power pulsates 60 times per second). One advantage of this is that you can carry more power over a given amount of wire area. For example, if you had a single phase circuit made up of two 8AWG wires, then added a third 8AWG wire to turn it into a 3-phase circuit, you could carry 3x the power, despite only increasing the total amount of wire by 1.5x. Or, to put it another way: a 3 phase circuit can transmit 2x as much power per unit area of wire used. However, this has nothing to do with the motor - just the circuit supplying it.

[John TenEyck]

OK, I have some data. Here's a photo of the motor plate:





Incoming line voltage was 243. Voltage when planing a board was 238. I pulled the access panel off the cabinet. One capacitor was accessible.



I finagled the ammeter around one of the leads. It read 2.7 amps while the motor was running.

Any feedback is greatly appreciated.

John

[John TenEyck]

John, I know you quoted that from some internet source, but it is absolutely incorrect. A HP is a HP, regardless of how it is generated.

I think the source you quoted was trying to explain one of the very fine nuances of 3 phase power, which is that the net flow of power to a motor does not vary with time (unlike a single phase circuit, where the power pulsates 60 times per second). One advantage of this is that you can carry more power over a given amount of wire area. For example, if you had a single phase circuit made up of two 8AWG wires, then added a third 8AWG wire to turn it into a 3-phase circuit, you could carry 3x the power, despite only increasing the total amount of wire by 1.5x. Or, to put it another way: a 3 phase circuit can transmit 2x as much power per unit area of wire used. However, this has nothing to do with the motor - just the circuit supplying it.

Thanks Dan. That makes perfect sense.

John

[Derek Cohen]

John, electricity is the black art to me, so my suggestion may be completely irrelevant. Probably ...

In cases where power has dropped off, it can be a linkage that is not transferring this along the chain. In the case if a table saw or bandsaw, the first item I look at is the belt. Has the tension dropped off? Not sure if this applies to your machine, but it is so elementary that it may go overlooked.

Regards from Perth

Derek

[Brian Holcombe]

Turn the machine by hand and see if there is any resistance, if so something is worn.

Some of the European equipment that is advertised as single phase from the 80’s and 90’s seems to use a 3ph motor and attach capacitors to one of the line inputs. The motors don’t have a lot of power by comparison to a normal 1ph setup or 3ph setup.

I would replace that motor with the same frame size 1ph motor or 3ph motor. I’ve bought a couple motors from an Italian brand Lafert, they’re really high quality and once in a while I can find them on eBay in the specs I need, often brand new old stock.

[Rod Sheridan]

Hi John, it looks like a 3 Hp motor, (CAV 3).

The capacitor current and line voltage look fine, it may simply be a bit undersized.

Obviously the narrower the workpiece the deeper cut you can take for a given motor power.

Thanks for taking the measurements.

Regards, Rod