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  1. #31
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    Ethan (47)
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    Re: HF now in Cary

    Quote Originally Posted by gmakra View Post
    Ethan sorry I don't mean to sound like a #### some of what you said is correct but most of it falls under Brandolini's law.
    And contrary to popular belief breakers usually fail by tripping at a higher amperage than lower.
    I stand by my comments get the name plate info off the motor and get some amp readings.

    Where we did you get from any of what I said that I ever suggested a breaker was likely to trip at a lower amperage than it’s rating? The contact damage they incur from repeated tripping under heavy load (particularly during initial surge current) or shorts can, however, make them less forgiving of minor overloads over time due to added heating within the breaker from increased contact resistance, but never did I say or suggest they were likely to trip in the absence of an overload, quite the opposite.

    Not only that, I specifically go on to argue that the OP is almost certainly operating in excess of their 20A circuit when operating both an upgraded DC (likely a 10-12A 1HP motor) with a new upgraded impeller and a power tool (12-15A) on the same circuit, especially once the startup surge of the second device is accounted for on an already heavily loaded circuit. This is why such loads are never recommended to be placed on the same circuit as a simple matter of good practice.

    If there is a particular aspect of my post that you would like to refute I would be more than happy to have that discussion, but to say “some of what you said is correct but most of it falls under Brandolini’s law” is the very definition of that law as you cast aspersions on everything without ever actually refuting anything whatsoever thus ensuring a meaningful discussion can not be had.

  2. #32
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    Re: HF now in Cary

    Ethan I am not going to get into a ####ing match with you.
    Nowhere in this post does the OP give any electrical data to make any kind of informed trouble shooting.
    The in rush for a motor rule of thumb is seven time the run amps.
    It can be higher on heavily loaded motors.
    Breakers do not have two different trip mechanisms because it will trip on time over current.
    That's why on a dead short it will trip very fast and on an overload it can trip a bit more slowly.
    The cold start on a fan is pure nonsense,
    And yes I am quite familiar, pre and post rotational vanes, VFDs Reeves drives, variable pitch axial fans and so on the resultant effect on CFM and AMP draw.
    If you look at my profile you will see I was in the HVAC business for many years.
    If you want if will be happy to send you published information to read.
    A good starting point would be
    https://www.amazon.com/HVAC-Equation...rules+of+thumb

  3. #33
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    Charlie (73)
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    Re: HF now in Cary

    Bottom line!

    Fan/blower manufacturers design their units to produce the maximum air flow/CFM using the minimum required horsepower. (Everything costs $$$$$). Whether it is a 2 HP unit or a 100 HP unit, any time you increase air flow, (either by increasing impeller size or increasing RPM), you will most likely over load (amperage draw) the motor. This was mentioned in an earlier thread in this post.

    DC units are designed with filters installed. They will usually state not to run unit without the filter. As mentioned before, air flow increases because of less restriction without the filter, which will increase amperage draw above the motor rating.

    By increasing impeller diameter, air flow has increased, amperage draw has increased, causing the 15 amp breaker to trip. Now a 20 amp breaker is installed on (probably) existing 14ga wire (rated at 15 amp) which can create a fire hazard. I would "never" allow this in my shop.

    Following is a section out of New York Blower Engineering Handbook:

    "If the fan speed is increased 10% in a fixed system, the volume flow through the system will increase 10%, the system resistance will increase 21% and the fan BHP will increase 33% according to the fan laws.
    The fan laws cannot be applied selectively, only simultaneously".

    Trying to get more airflow using the same HP is like trying to lift 100 tons with a 1 ton chain hoist. Something is going to break.

    Just my 2 cents.

  4. #34
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    Re: HF now in Cary

    First off, thank you guys for the wonderful explanations, your knowledge is invaluable to have here, thank you very much for sharing.
    Just to clarify some things, my DC is the only thing on an isolated 20A circuit, there are no other tools present on this circuit.
    I have only tripped this breaker twice so far, not multiple times. I should also clarify that one of the trips happened with the wireless remote plug inline with the DC and one happened without. No great data points there, but thought I would share.

    I will get the info from the motor, this is the model: https://www.harborfreight.com/2-hp-i...tor-97869.html

    And to followup with previous poster, yes, the amperage draw needs to be tested to know exactly what is going on. I may have to upgrade the circuit to 30A, not looking forward to pulling 10ga through 1/2" EMT The EMT run for the DC is the longest in my garage.

  5. #35
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    Re: HF now in Cary

    Stu, HF shows the motor rated @ 20 Amp.

    For the $$ spent, I would have purchased another HF collector for $210 and doubled the air flow.

    In (under) my shop there are (1) 3 HP and (5) 2 HP blowers, along with (7) 6 HP rated (yeah, right, more like 1/4 HP) vacuums. The blowers all exhaust directly outside with no filters/cyclone.

  6. #36
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    Re: HF now in Cary

    Quote Originally Posted by gmakra View Post
    Ethan I am not going to get into a ####ing match with you.
    Nowhere in this post does the OP give any electrical data to make any kind of informed trouble shooting.
    The in rush for a motor rule of thumb is seven time the run amps.
    It can be higher on heavily loaded motors.
    Breakers do not have two different trip mechanisms because it will trip on time over current.
    That's why on a dead short it will trip very fast and on an overload it can trip a bit more slowly.
    The cold start on a fan is pure nonsense,
    And yes I am quite familiar, pre and post rotational vanes, VFDs Reeves drives, variable pitch axial fans and so on the resultant effect on CFM and AMP draw.
    If you look at my profile you will see I was in the HVAC business for many years.
    If you want if will be happy to send you published information to read.
    A good starting point would be
    https://www.amazon.com/HVAC-Equation...rules+of+thumb
    With respect, there is a reason we call the circuit breakers in our home load centers magnetic-thermal circuit breakers (that is if we wish to use their full name). They use a bimetallic strip to trip thermally on low grade long term overload and a magnetic solenoid to trip nearly instantly on severe overloads. With a quick search one can find plenty of tear downs, photos, and demonstrations of these circuit breakers and how each trip mechanism functions, or simply download the data or product sheets from Schneider, GE, etc.

    There was another thread where we had been discussing his electrical setup (at least I believe it was from the same member as it concerned remote DC activation using a plugin lighting wireless remote plus an added contactor) though it was always a bit vague as to which 120V HF DC model they were upgrading as that has only now been clarified — so, yes, I had the incorrect model in mind and to question me on that aspect of my reply is perfectly fair.

    I would point out that I never cast any aspersions whatsoever on your qualifications nor did I ever question your competence in your professed area of expertise and I am uncertain as to why you feel that I have.

    I do hope you have a great day remainder of the day.

  7. #37
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    Re: HF now in Cary

    One thing I have learned after purchasing and installing all types of equipment all over the world for 30+ years is that if the manufacturer says "don't", then don't.
    I have also learned that they probably know more about the equipment than I do. That's what installation/operation manuals are for.

  8. #38
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    Re: HF now in Cary

    I commented earlier that I had experienced a few trips on my shop 20A, 110V shop circuit. The first few happened when I turned on my 1.75hp SawStop which also turns on my 10 amp rated shop vacuum. The total of the rated amps is over 20 so I thought maybe it was just too much tools - despite the fact that the auto-on switch says it will do what I am doing. Then it tripped when I was running a board through my old Ryobi AP-10 planner. At the time of my last post, I did not know the current rating of the planner but I've since looked it up, it is 13A. So a tool rated to draw no more than 13A tripped a breaker rated to trip at 20A. The planner was taking a light cut and is a universal motor so it was not drawing even it's rated power. When the breaker was reset, the planner worked fine.

    I gave this detailed example to illustrate the fact that breakers go bad and trip when they should not. I've had it happen on other loads before. I think we need to keep in mind that may be the problem.

    I added an outlet on another 20A load recently so I pulled that breaker. I swapped it with my shop breaker. Now I need to get some other projects done so I can make some more wood dust and see if that "fixed" it.

  9. #39
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    Re: HF now in Cary

    Posted by Stu: (Minor update, I was able to trip the breaker on startup on 2 occasions so far with the new impeller installed. Only on cold starts).

    The increased air flow has increased amperage draw above the capacity of the existing circuit.

    Install the DC on a 30 amp circuit and you will eventually burn up the motor. Windings in a motor are rated for a given amp capacity. When you start a motor the initial amp draw can momentarily be 200-300% more than running amp draw. (Breakers are designed to handle this surge but can eventually break down and trip prematurely). That is why blowers are usually rated to be started only so many times per hour. Most motors are rated by duty cycle, ie., 50%, etc. That means you should run it only for 30 minutes non stop. Most industrial motors are rated 100% which means they can run forever. That's why industrial motors cost more. Welders are rated by duty cycle. A $200 unit can only be used X amount of time before a required shut down/cool down time, a $1000 unit can be used XXXXXXX before shut down.

    Nothing is free. If you want to increase air flow you must increase HP. You may squeeze a small increase depending on how close the fan was designed to max.

    If you want more air get a larger fan or get a second dust collector.

    I'm done now! Lol


    Last edited by Charlie; 01-04-2019 at 04:14 PM.

  10. #40
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    Re: HF now in Cary

    Thought I would share the install pics of the 2 stage portion of the DC now. This is with the contactor inline with the wireless remote and with the new filter, SDD, 55gal drum installed.
    All that is left is to run lines to the equipment, that will be its own set of challenges. The filter hangs a little askew, but its not going anywhere. It has tripped 1 time in this new configuration. I still need to try replacing the breaker to see if that helps. I appreciate all the conversation regarding the electrical portion of this. I certainly would not have attempted these modifications had I not see them done elsewhere by other people with positive results. I think this system will work well for my garage shop and help keep the dust out of the air.

    20190106_173056.jpg20190106_130049.jpg

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