Thread: Thoughts on These 3hp Machines

I'd go with the Sherwood model as the design with the airflow direct into the filter bag housing will be superior.
You should be able to flip the motor upside down to accept ducting from above.

The Sherwood filters are pretty ordinary and not as good as the thick Carbatech ones. I don't know with the Leda ones are like.
Anyway this shouldn't matter as all DCs should be vented or located outside a shed.

Thanks Bob, I kinda thought as much.

Is the 2900cfm on the Sherwood Vs the 2500cfm on the Leda due to the extra ducting on the Leda machine?

The manufacturer CFMs ratings on both machines and nearly ALL DCs are fantasy numbers.
They are based on No filters, ducting, junctions, machinery connections, a flawed industry standard testing protocol, and whatever the importer wants to hear from the manufacturer.

Whenever 6" ducting is used on any widely commercially available 3HP DC in a real WW dust collecting situation the 6" ducting itself becomes the limiting step, so the most air you can get through is ~1250 CFM, by the time the filters clog up a little and a machine that breathes poorly is added it will be below 1000 CFM. For 4" ducting the limit is around 425 CFM.

To get more air through a 6" duct requires a bigger impeller and thus a bigger motor. The 4HP Clearvue can get about 1400 CFM though 6" ducting. To get even more air flow bigger DCs like 20HP, 20" impeller systems use 12" ducting or larger.

However you can't using 8" or bigger ducting on a 3HP system because the speed of the drops as the size of the ducting increases which can result in wood chips falling out of suspension.

I've got one of the Sherwood ones. The inlet on it is 8" and it will also need a 15 amp powerpoint. I ended up using 6" duct (150mm PVC pipe) across about 9m. With the 6" duct as close as possible to the machine and then a short bit of 4" flex it works just fine as it is with the inlet at the bottom and nice gentle curves to get from there to the destination. So far easily runs 2 4" inlets at once. Can't comment on the filters as I've got it a a separate shed but it doesn't seem any dustier in there than before.

I was just about to ask the same question as this as I want to modify my DC7 to take the duct from the ceiling.
Just confirming, does the fan care what orientation it is in? I know the motor does not care too much, just unsure if there is a difference to the airflow.

Thanks.

Originally Posted by markdem

I was just about to ask the same question as this as I want to modify my DC7 to take the duct from the ceiling.
Just confirming, does the fan care what orientation it is in? I know the motor does not care too much, just unsure if there is a difference to the airflow.

Thanks.

It doesn't matter about orientation. Just remember to get the air curving the same way.

Excellent. I just wanted to make sure before I start modifying.

Thanks

my workshop is 6mx 9m. I use to have the Leda design extractor and they are underpowered for the size of the workshop.
You may need something like a 4-5hp extractor.

my current extractor is a 5hp bag house extractor.

Size of shed assumes
- you are going to run ducting all over the shed.
- your machines will bigger hence make more dust.

However, if your machines are small and you are only going to use one end or one corner for dust making activities then you can get away with a smaller DC.
This is where modification of machine ports becomes critical