3HP Baldor Question

[Heather Thompson]

I have two pieces of equipment in my shop with 3HP motors, an Oneida dust collector and a PM66. When I hit the switch on the dust collector it takes a second or two to come up to power, the PM66 is a totally different beast, you hit the power there is no hesitation (not a soft start machine). :eek: I talked to a sparky friend of mine this morning to see if there was any way to tame the beast (industrial rheostat) maybe, he was not sure and recommended that I contact Baldor directly to pose the question. Thought I would toss this question to the group for input.

Heather

[Bruce Page]

The Oneida is spinning up the mass of the impeller along with the air it’s trying to suck in. The PM only has the arbor & blade to deal with. I’m not sure why you would want a “soft start” on the TS.

[mike wacker]

Heather,

One possible reason comes to mind. The DC probably has more mass to get moving, the Fan impellor (sp) and the air itself. Hence you can notice a period of time it takes to reach full speed. Then once it is at full speed it is under load the whole time.

The PM66 has much less mass to get spinning, just the blade. Once it is up to speed it is "coasting" until you feed the beast.

[Art Mann]

Why in the world would you want to do that? It is harder on a motor if it starts up slowly than if it starts quickly.

The slower startup of the Oneida is probably due to the greater inertia in the cyclone as compared to the saw blade.

[Dennis Ford]

Single phase motors are not compatible with soft start systems. The reasons for the difference you noticed are correctly noted in previous messages.
:rolleyes:

[Heather Thompson]

The Oneida is spinning up the mass of the impeller along with the air it’s trying to suck in. The PM only has the arbor & blade to deal with. I’m not sure why you would want a “soft start” on the TS.

Bruce,

I have a Betterley ZCI and there are times at start up that it will actually lift the back end of the of the aluminum plate, do not want to see a chunk of aluminum rocketing through the shop wall. I have used the same style insert on a Delta contractor saw and the design is such that there is a finger at the back to prevent lift, not the case on the model designed for the 66. I will be calling Betterley Industries to question this issue tomorrow morning.

Heather

[Bruce Page]

Heather, this is my ZCI that I made for my Unisaw based on the original throat plate. Note the dowel pin. The pin inserts under the table at the backside of the opening and holds it from lifting. I don’t think I would feel comfortable if the ZCI just sat there without something holding it in.
I don't think you have an issue with your TS.

[Michael Lutz]

I have a 5HP PM 66 and I have the same reaction from the motor. It starts almost instantaneously.

Mike

[Heather Thompson]

Heather, this is my ZCI that I made for my Unisaw based on the original throat plate. Note the dowel pin. The pin inserts under the table at the backside of the opening and holds it from lifting. I don’t think I would feel comfortable if the ZCI just sat there without something holding it in.
I don't think you have an issue with your TS.

Bruce,

I agree, the first Betterley plate that I had on the Delta contractor saw had a finger (pin) in the back of the plate, the one designed for the PM66 has nothing and no real space to drill and install one. Will contact the manufacturer tomorrow to discuss the safety issues with this and then contact Eagle America (place of purchase) concerning return. When I bought the saw used it did not come with an insert.

Heather

[Lee Hingle]

Bruce,

I have a Betterley ZCI and there are times at start up that it will actually lift the back end of the of the aluminum plate, do not want to see a chunk of aluminum rocketing through the shop wall. I have used the same style insert on a Delta contractor saw and the design is such that there is a finger at the back to prevent lift, not the case on the model designed for the 66. I will be calling Betterley Industries to question this issue tomorrow morning.

Heather

Heather,
Have you run the blade up and down through the insert while it's spinning? I have the exact same set up and have never had any sort of issues with the blade teeth contacting the insert and lifting. I also have no pin holding the insert in. Do you have any slop in the arbor/blade assy?
Lee

[Bruce Wrenn]

The value of the start capacitor has to do with start up speed also. I agree with other posters about the mass of impeller and air in DC. A friend had a
Jet 15" planner that would spin the belts on start up. Jet suggest that he try a smaller start cap. He did and it worked. There is a limit as to how much smaller you can go though.

[Heather Thompson]

Heather,
Have you run the blade up and down through the insert while it's spinning? I have the exact same set up and have never had any sort of issues with the blade teeth contacting the insert and lifting. I also have no pin holding the insert in. Do you have any slop in the arbor/blade assy?
Lee


Lee,

I clamped a 2x4 over the insert and slowly raised the blade through the insert, then raised and lowered it about 5 more times. I have just recently set the saw up, dial indicator to Master Plate for miter slot alignment and fence, checked arbor for runout, no slop in bearings. I checked the blade for tolerances, all is good.

Heather

[Tom Veatch]

Lee,

I clamped a 2x4 over the insert and slowly raised the blade through the insert, then raised and lowered it about 5 more times. I have just recently set the saw up, dial indicator to Master Plate for miter slot alignment and fence, checked arbor for runout, no slop in bearings. I checked the blade for tolerances, all is good.

Heather

Side to side slop of the insert in the cavity? Would only take a few thousands to let the insert make light contact with the side of the blade until the kerf wears with use.

Can you thread a set screw into the side of the insert to take up any excess clearance?

[Heather Thompson]

Side to side slop of the insert in the cavity? Would only take a few thousands to let the insert make light contact with the side of the blade until the kerf wears with use.

Can you thread a set screw into the side of the insert to take up any excess clearance?

Tom,

The insert has spring loaded side plungers to eliminate vibration or side movement in the plate.

Heather

[Cliff Rohrabacher]

http://www.automation.com/store/p1030details22405.php

http://www.process-controls.com/raebrooke/soft_start_controls.htm

[Heather Thompson]

Cliff,

Thank you for the information, that was exactly what I was looking for, my not need it at this point but definately will file away for future applications.

Heather

[Andy Calenzo]

Heather,

This is Andy, one of the engineers at Oneida Air Systems. I just wanted to chime in here and echo Bruce Page's, Mike Wacker's and Art Mann's posts and state that the difference between how the unloaded (unloaded = no wood placed near the saw blade) PM66 starts up as compared to the Oneida has to do with the inertia of the impeller. Isaac Newton's Law of Inertia (first law) says a body will remain at rest unless acted upon by an external force. This means that while the Baldor motor wants to obtain the rotational speed marked on the nameplate (3450 RPM) in an instant, the 11 pound aluminum impeller is trying to hold it back. Also, this impeller is trying to pump air from the moment that the motor begins to spin it and this acts to hold the motor back as well. It is a fact that the weight of the wheel (and the effort required for the impeller to pump air through the system - even at the slow rotational speed of the impeller that exists just after the motor starts) does succeed in holding the motor back for around a second or two causing it to draw inrush current approximately 6 times higher than full load amperage (note that this inrush current dissipates in this 2 second time period) marked on the motor nameplate. There is a potential situation where the PM66 would behave in a similar fashion to the dust collector when it starts up. The situation to which I am referring is what would occur if you pushed a board against the stationary blade on the PM66 while it is at rest and then hit the start button. The PM66 would struggle to get to full speed until the teeth on the saw blade began cutting their way through the board. Once the cutting action begins and the board travels past the teeth of the saw blade, the blade can spin with less resistance which lowers the amp draw of the motor. This is almost exactly the way the Oneida behaves as it comes up to its steady state rotational speed of 3450 RPM.

I hope that this clears it up. Let us know if you need anything else.