Electrical/dust collection questions

[DonHo]

I currently have the GMC dust collector that was a closeout from Lowes it's listed at 7 amps. I have the Sears switch/plug box that you plug your tool into and also the dust collector and the switch will start/stop the dust collector when you turn your tool on or off. I like this set up as it's very handy not to have to switch the collector seperately. Now I'm thinking of switching to a 1 hp collector that is listed at 12.4 amps. I know the listed amps are max, would there be a problem with using the new DC with the BT3 on a 20 amp circut?

My second question is, the 12.4 amp collector I'm looking at is the DC1BXL 1hp from Penn State, they list this as 850 CMF. They also have a 1 hp "powerful mini" collector that they list at 6.8 amps with 914 CMF (because of higher rpms). Does this sound right and if so would the higher rpms increase the noise greatly?

Thanks for your input.
DonHo

[JimD]

Don,

I would not do it. I have my 1hp DC on a separate circuit from my BT3100. You might be able to start both a DC and the BT3100 on a 20 amp circuit but once the BT3100 starts to work a little, I am pretty sure you can count on the breaker tripping. It will not hurt anything to try as long as the breaker works, however. The only way I can see that the proposed setup will work, however, is if the breaker doesn't.

Jim

[Russianwolf]

I've been using my 2hp HF DC and BT3100 on the same circuit (all the plugs in my basement are on the same breaker, all the lights on another). I haven't noticed any problems with running the two tools at the same time. Ditto for my Delta planer and DC. Granted they are not starting up at the same time, which may draw more amps.

In fact when I'm down there I have 2 48inch florecent lights,plus the two tools going at the same time on the one circuit.

I believe it's a 20 amp circuit, but it could be a 30 amp. I'll have to look at some point.

[JR]

I couldn't run my HF DC and the BT on the same circuit. It would trip the breaker. I put the DC on a separate circuit and operate it with X10 with remote control.

You might look at LCHIEN's recent thread showing his desing for a transformer-enabled DC circuit. You can use the Sears auto-switch with it if you want.

JR

[JimD]

I based my comments on the fact that I have my 1 hp Delta DC and the lights in my shop on the same circuit - a 15A. When I start the DC, the lights momentarily dim. The BT3100 probably does not pull a lot until you are in the middle of a thick rip or crosscut. I still think that a properly working 20A breaker will trip with the DC running when the BT3100 gets to working hard. I have no direct experience so maybe I'm wrong but that is my guess.

Jim

[LCHIEN]

Even a 7A DC with the BT on the same circuit (with or without the Sears autoswitch) is not the greatest setup.
went thru this in great detail about a month or two ago. Jim Frye who championed the Autoswitch admitted sometimes his BT tripped the breaker with the vac on the switch.

The DC will draw max current constantly.
The saw will demand up to 15 Amps when making difficult cuts. 15+7 = 22. You will then exceed the breaker rating. If making a long rip you can trip the breaker and you won't be getting maximum power from your BT.

A 12-13A DC will just be worse.
The 2 HP HF DC draws 15Amps all the time when working at rated air flow.
It practically needs its own circuit.

see this discussion
http://www.bt3central.com/showthread.php?t=19940

[DonHo]

Thanks for the replies. It seems the 12.4 amp DC wouldn't be prudent. How about the second part of the question? The "1 HP" DC that only pulls 6.8 amps? I think this should work as my present DC pulls 7 amps and I've had no problems, however I wonder if some part of the claims for this DC are wrong. For one thing why does this 1 HP DC pull 6.8 amps while the other pulls 12.4 amps? Also this one claims more CFM that the 12.4 one, because of higher rpms, does that sound right?

Thanks again,
DonHo

[LCHIEN]

Thanks for the replies. It seems the 12.4 amp DC wouldn't be prudent. How about the second part of the question? The "1 HP" DC that only pulls 6.8 amps? I think this should work as my present DC pulls 7 amps and I've had no problems, however I wonder if some part of the claims for this DC are wrong. For one thing why does this 1 HP DC pull 6.8 amps while the other pulls 12.4 amps? Also this one claims more CFM that the 12.4 one, because of higher rpms, does that sound right?

Thanks again,
DonHo

if you read my reply I don't think the 7 Amp DC with the saw is good either.
Higher Amps usually indicates moving more air.
Usually induction motors of 3400 RPM are used, the RPMs are about the same when properly loaded. The airflow is dictated by the size of the impellor assuming the motor is properly sized big enuf to turn it at that air flow.

There's detailed explanations in the link i provided. Did you read it?

[Russianwolf]

if you read my reply I don't think the 7 Amp DC with the saw is good either.
Higher Amps usually indicates moving more air.
Usually induction motors of 3400 RPM are used, the RPMs are about the same when properly loaded. The airflow is dictated by the size of the impellor assuming the motor is properly sized big enuf to turn it at that air flow.

There's detailed explanations in the link i provided. Did you read it?

Loring, he's talking about Penn States DC-5

This dust collector is small (18 lbs) but powerful and portable. It is perfect for the garage-sized shop. A powerful universal motor rotates at 6400 RPM, thus creating super suction and making it a perfect replacement for a standard vacuum or your shop vacuum.

the rpm's are way up on this unit. Given that DC's are one of Penn State's bread and butter items, I think they are fairly accurate with their claims. I was looking at this unit when I was in the market, but thought I wanted to pull more air, so went with the HF 2hp unit. as I mentioned. I haven't been tripping my breaker with the saw and DC on the same circuit, but I don't know the technical stuff.

[LCHIEN]

Loring, he's talking about Penn States DC-5

the rpm's are way up on this unit. Given that DC's are one of Penn State's bread and butter items, I think they are fairly accurate with their claims. I was looking at this unit when I was in the market, but thought I wanted to pull more air, so went with the HF 2hp unit. as I mentioned. I haven't been tripping my breaker with the saw and DC on the same circuit, but I don't know the technical stuff.

I guess I'm guilty of not checking all the facts. I did not know the PS DC-5 was a universal motor unit - usually induction motors are used because of the continuous operation. Maybe PS made it with a universal motor to keep down the weight and cost. I can't see that there would be much of a power/Airflow advantage, spinning the motor with impellor load at a higher speed would take more effort e.g. power. Moving air is work, so regardles of the impellor speeed and characteristics, to move more air per minute takes more power. I don't think you'll get drastic changes in net air flow for power even changing motor speeds and impellor sizes (assuming all the components are sized properly).

As far as the HF2 HP DC goes, I have checked mine at 14.7 Amps with the inlet ports wide open and low resistance Grizz canister on top. They pull the most power when moving the maximum air fow. On a 15Amp circuit with a 15A breaker that would leave zilch for the saw.
I have measured my BT3 and it takes 6-7Amps just to spin the blade.

Granted, if you choke off your DC with a single 10-ft run of 4" flex hose, it will probably drop the current down to 12-13Amsp (guessing here, i should measure it someday)
and your saw may run on the leftover current (because 15A breakers don't trip at 15Amps very fast)

[Russianwolf]

I guess I'm guilty of not checking all the facts. I did not know the PS DC-5 was a universal motor unit - usually induction motors are used because of the continuous operation. Maybe PS made it with a universal motor to keep down the weight and cost. I can't see that there would be much of a power/Airflow advantage, spinning the motor with impellor load at a higher speed would take more effort e.g. power. Moving air is work, so regardles of the impellor speeed and characteristics, to move more air per minute takes more power. I don't think you'll get drastic changes in net air flow for power even changing motor speeds and impellor sizes (assuming all the components are sized properly).

As far as the HF2 HP DC goes, I have checked mine at 14.7 Amps with the inlet ports wide open and low resistance Grizz canister on top. They pull the most power when moving the maximum air fow. On a 15Amp circuit with a 15A breaker that would leave zilch for the saw.
I have measured my BT3 and it takes 6-7Amps just to spin the blade.

Granted, if you choke off your DC with a single 10-ft run of 4" flex hose, it will probably drop the current down to 12-13Amsp (guessing here, i should measure it someday)
and your saw may run on the leftover current (because 15A breakers don't trip at 15Amps very fast)

I think I'm on a 20 amp circuit. And I'm running a good 20ft of 4" flexhose between the two with a separator in between. Don't know if any of that makes a difference, but it's working okay so far.

The only time I've ever had a problem with tripping the circuit I was running the BT and shopvac while ripping a 16/4 piece of Wenge. I'm sure that ran the saw up in amperage pretty good.