Delta 50-760 separator and outside vent

[Upnorth]

I am in the planning stage of a separator and outside vent for my Delta 50-760. Is it ok to have 6" and 4" Y intake (PVC custom made using Digital Pipe Fitter) and a 5" to the DC ? Also, would my vent hood design be ok or could it create to much back pressure ?

[phil (admin)]

Looks like it would work fine.

[Upnorth]

Thank's Phil

[WayTooLate]

Up-
I think your outside vent is a great idea.  Bill Pentz has advocated that for a long time... 

If your outside outlet is 'large', then the airflow will pass on through and you will collect very few fines in your 'drop bag'.  If the outlet is 'small', then it will restrict air flow and performance will suffer. 

Depending on your blower performance, it may not matter how much you enlarge the opening.  If your intake properly 'throttles' the amount of air the blower can gulp at a time, then you can't overload the motor.  When this protection is in place, your outlet side can only 'hurt' performance if it gets restricted. 

If the intake can take in large amounts of air, then the motor could be overloaded.  In these designs, the outlet is designed to provide enough back pressure to prevent overload and excessive current draw on the motor.   

If you are using a HF blower (or other over-the-counter, packaged blower system), they are designed to be 'under-performers' that cannot hurt themselves.  We lose a little performance - they lose a lot of potential problems.  If you start putting together systems yourself using blower packages from places like Grainger's, then you have to pay a lot more attention to those details... 

Let us know how your system turns out.  It looks like a 'clean design' that should work well for a long time! 
- Jim

[Upnorth]

Jim,

I am not sure I understand how I could overload the motor (1-1/2 hp) with to much air coming in... Theoretically I could fry the motor simply by running it with nothing connected to the 5" intake ?

I thought that the risk of overloading was a consequence of to much restriction on the intake side ex: A single 2-1/2" x 25' hose connected to the 5" intake would probably be very inneficient and would certainly put a lot of strain on the motor.

Richard

[phil (admin)]

Jim,

I am not sure I understand how I could overload the motor (1-1/2 hp) with to much air coming in... Theoretically I could fry the motor simply by running it with nothing connected to the 5" intake ?

I thought that the risk of overloading was a consequence of to much restriction on the intake side ex: A single 2-1/2" x 25' hose connected to the 5" intake would probably be very inneficient and would certainly put a lot of strain on the motor.

Richard

It is actually the opposite.  The more air being moved, the more work the motor is doing and the more current it will draw the the warmer it will run.  Closing off either the inlet/outlet so it moves no air will cause the wheel to free-wheel (moving no air) which is actually EASIER for the motor.

[WayTooLate]

I know - it seems counter-intuitive... 

When the system seems to 'scream' because it is starved for air, the motor is not working hard.  When the system is 'wide open' and gulping in large amounts of air, the motor is heavily loaded. 

That is why most DC units that we buy have been designed to prevent this.  Even if you remove the intake duct, the cover plate of the housing still provides restriction.  The outlet port of the blower also defines the max throughput.  Slightly less performance means a longer 'happy-life' for the blower motors. 

Let us know how your system works when you get it installed - I think it will be a good installation! 

[Upnorth]

 ::) Now it makes sense, Thank's