Central Machinery Dust Collector (110V) surge amps = >78 amps

[WI/MI Border]

I'm just wondering if 78A is a normal infeed/starting amp draw for such a piece of equipment. I am trying to get the DC to start on my off-grid electrical system but it doesn't play well with the inverter. I do have some options to remedy the problem (second split phase inverter and/or using the inverter's pass-through capability) but thought I should check the community to see what their experience with these Harbor Freight DCs. Maybe the motor is not operating efficiently?

Thanks, Tim

Some specs of the inverter below;
The inverter features a surge capacity of 12,000 watts for approximately 3.5 seconds (or 11,000W for 5 seconds). This allows it to handle heavy startup loads for motors and appliances. It has a maximum continuous output of 6,000W (25A at 240V) and supports a 50A grid/generator bypass.

 

[wyliesdiesels]

a pic of the motor nameplate would be helpful

 

[PCustoms]

I'm just wondering if 78A is a normal infeed/starting amp draw for such a piece of equipment. I am trying to get the DC to start on my off-grid electrical system but it doesn't play well with the inverter. I do have some options to remedy the problem (second split phase inverter and/or using the inverter's pass-through capability) but thought I should check the community to see what their experience with these Harbor Freight DCs. Maybe the motor is not operating efficiently?

Thanks, Tim

Some specs of the inverter below;
The inverter features a surge capacity of 12,000 watts for approximately 3.5 seconds (or 11,000W for 5 seconds). This allows it to handle heavy startup loads for motors and appliances. It has a maximum continuous output of 6,000W (25A at 240V) and supports a 50A grid/generator bypass.

How did you measure 78 amps?

Simple answer, no, that's insane for 120 volt motor

 

[Jlanciani]

How did you measure 78 amps?

Simple answer, no, that's insane for 120 volt motor

Inrush current on an induction motor is 6-10x full load current. 78 amps is a realistic value.

 

[micromind]

The starting current of a basic 1HP motor at 120 volts will be somewhere around 90 amps, higher if it's an energy-efficient model.

78 is reasonable for a 3/4HP motor.

Inverters don't like high currents like this.

 

[PCustoms]

Inrush current on an induction motor is 6-10x full load current. 78 amps is a realistic value.

Ok, maybe it's been a while since I've had to deal with it, but isn't his inverter OK past 90A for a few seconds? Shouldn't inrush be less then 5 seconds?

 

[WI/MI Border]

How did you measure 78 amps?

Simple answer, no, that's insane for 120 volt motor

PC...,
I measured in-rush current with a clamp meter on the positive wire inside the sub-panel. I measured using grid power, not off-grid from the inverter.

I'm getting replies that 78a is insane and others saying 90a would be OK. So I'm at a loss as to whether the motor is faulty or operating normally. PC, you (and others) have helped me on numerous occasions with wiring my new sub-panel. I have to give you the benefit of the doubt. If my measuring method is faulty that might have produced an incorrect value or I am interpreting it incorrectly. The clamp meter has a Min/Max button and after repeated starts (on grid) the average in-rush showed as ~78a. It is not a meter that has "in-rush" features, just min/max.

wdiesels,
The motor is only wired internally for 110v. It does not support 220v. That is the first thing I checked, hoping I could wire it for 220v which might help lower the amps on each leg. If that addresses the question you have about the motor, great. But I am not an expert in these matters.

I'm considering upgrading to a 220v dust collector but thought I'd ask a few questions here first. Regardless, I have another 6K split phase inverter on order and hope that the two inverters will split the load on a single leg. If not... on to a 220v dust collector.

 

[WI/MI Border]

The starting current of a basic 1HP motor at 120 volts will be somewhere around 90 amps, higher if it's an energy-efficient model.

78 is reasonable for a 3/4HP motor.

Inverters don't like high currents like this.

Here is one spec on the inverter...

The EG4 6000XP inverter features a 12kW (12,000W) surge capacity for up to 3.5 seconds to handle high in-rush currents, such as those from well pumps, AC units, or motors. It supports 6kW continuous output, managing heavy loads that might trip lesser inverters.

 

[micromind]

Here is one spec on the inverter...

The EG4 6000XP inverter features a 12kW (12,000W) surge capacity for up to 3.5 seconds to handle high in-rush currents, such as those from well pumps, AC units, or motors. It supports 6kW continuous output, managing heavy loads that might trip lesser inverters.

It looks like the inverter can handle it but what about the batteries, etc. that supply the DC to the inverter?

 

[PCustoms]

PC...,

I'm getting replies that 78a is insane and others saying 90a would be OK. So I'm at a loss as to whether the motor is faulty or operating normally. PC, you (and others) have helped me on numerous occasions with wiring my new sub-panel.

Go with the others on this one, I guess it's normal.

It seems odd to me though that you have a 3-5 second peak buffer at 90a plus, but it's still tripping. Seems long a long duration for inrush current.

 

[mike93lx]

Maybe install a soft start

 

[mm08822]

Still need the pic of motor nameplate.

 

[mike93lx]

Still need the pic of motor nameplate.

Why? What is uncertain that will be cleared up with that Pic?

 

[PCustoms]

I am curious now, how critical is a dust collector on an off-grid setup?

 

[mike93lx]

I am curious now, how critical is a dust collector on an off-grid setup?

If you are woodworking off grid, pretty important? Critical is probably a stretch

 

[LopezBart]

It looks like the inverter can handle it but what about the batteries, etc. that supply the DC to the inverter?

A 90amp load at 120V would be 450 amps at 24V or 225 amps at 48V (assuming 100% efficiency). All cables, connections, etc. need to be low enough resistance to prevent excessive voltage drop which will cause the inverter to reset or go into battery protection mode.

 

[mm08822]

Why? What is uncertain that will be cleared up with that Pic?

If the info contains a code letter it would easily clear up the initial uncertainty of inrush value.

 

[mike93lx]

If the info contains a code letter it would easily clear up the initial uncertainty of inrush value.

Thanks.

What are the letter codes and what would they tell us?

 

[WI/MI Border]

Battery "Discharge Current = 200A"

Here you go mm...
Dust collector label. The only label found after removing the wiring cover (switch cover) and capacitor cover. I don't know if this is a capacitor start or capacitor run motor.

Thanks for the interest in this puzzle : )

I think I'm going to ask on the lumberjocks forum for someone to measure the current surge on the Bauer dust collector. That's the one I'm considering as it is a true 120/240v motor. Hopefully someone there can tell me the 120 and 220v current surge.

 

[rlitman]

...I think I'm going to ask on the lumberjocks forum for someone to measure the current surge on the Bauer dust collector. That's the one I'm considering as it is a true 120/240v motor. Hopefully someone there can tell me the 120 and 220v current surge.

That depends highly on what it's plugged into. Your best bet, as mentioned above, is to look into a soft start.

 

[mike93lx]

Battery "Discharge Current = 200A"

Here you go mm...
Dust collector label. The only label found after removing the wiring cover (switch cover) and capacitor cover. I don't know if this is a capacitor start or capacitor run motor.

Thanks for the interest in this puzzle : )

I think I'm going to ask on the lumberjocks forum for someone to measure the current surge on the Bauer dust collector. That's the one I'm considering as it is a true 120/240v motor. Hopefully someone there can tell me the 120 and 220v current surge.

Measuring inrush current is not something most people have the equipment to do

 

[WI/MI Border]

Measuring inrush current is not something most people have the equipment to do

Yep, understood. I just learned how to measure surge amps with my meter (assuming I did it right). I'm just hoping one 120v and one 240v user just might have that ability.

I did some research on soft starts a little while ago. Most folks replied that they are very useful for three phase motors and some single phase motors but I was advised to not waste my time and money trying to make this particular cheap Chinese motor and heavy impeller start with a soft start. I don't completely understand why but I value their experience.

I'm going to wait and install the second split phase inverter and hope for the best. I also need to study the Luxpower user manual. I think that it can be programmed to use "priority battery" and use grid when a load demands more than the inverter is able to feed with battery. Don't quote me on that theory. I have some studying to do.

Thanks again all.

 

[PCustoms]

I'm going to wait and install the second split phase inverter and hope for the best. I also need to study the Luxpower user manual. I think that it can be programmed to use "priority battery" and use grid when a load demands more than the inverter is able to feed with battery. Don't quote me on that theory. I have some studying to do.

Thanks again all.

So you actually have grid power at this location?

 

[mike93lx]

Yep, understood. I just learned how to measure surge amps with my meter (assuming I did it right). I'm just hoping one 120v and one 240v user just might have that ability.

I did some research on soft starts a little while ago. Most folks replied that they are very useful for three phase motors and some single phase motors but I was advised to not waste my time and money trying to make this particular cheap Chinese motor and heavy impeller start with a soft start. I don't completely understand why but I value their experience.

I'm going to wait and install the second split phase inverter and hope for the best. I also need to study the Luxpower user manual. I think that it can be programmed to use "priority battery" and use grid when a load demands more than the inverter is able to feed with battery. Don't quote me on that theory. I have some studying to do.

Thanks again all.

Soft starts are used on single phase air conditioner compressors all the time, including one of mine, and they work great.

 

[dave*99]

My dust collector has a large heavy impeller. It starts slower than my air conditioner compressors. Much slower by the sound of things. Could be a factor when considering a soft start kit.

 

[wyliesdiesels]

Simple answer, no, that's insane for 120 volt motor

nope it actually isnt. in-rush can be that high

 

[wyliesdiesels]

PC...,
I measured in-rush current with a clamp meter on the positive wire inside the sub-panel. I measured using grid power, not off-grid from the inverter.

make and model of meter?

I'm getting replies that 78a is insane and others saying 90a would be OK. So I'm at a loss as to whether the motor is faulty or operating normally. PC, you (and others) have helped me on numerous occasions with wiring my new sub-panel. I have to give you the benefit of the doubt. If my measuring method is faulty that might have produced an incorrect value or I am interpreting it incorrectly. The clamp meter has a Min/Max button and after repeated starts (on grid) the average in-rush showed as ~78a. It is not a meter that has "in-rush" features, just min/max.

Then the meter cannot measure in-rush properly. you need a meter with special circuitry in order to be able to properly measure in-rush current.

wdiesels,
The motor is only wired internally for 110v. It does not support 220v. That is the first thing I checked, hoping I could wire it for 220v which might help lower the amps on each leg. If that addresses the question you have about the motor, great. But I am not an expert in these matters.

no id like to see the nameplate.

 

[wyliesdiesels]

Go with the others on this one, I guess it's normal.

It seems odd to me though that you have a 3-5 second peak buffer at 90a plus, but it's still tripping. Seems long a long duration for inrush current.

in-rush current lasts a few hundred millisecond, NOT 3-5secs

 

[tool_scrounge]

In general, The Asian made motors had higher current inrush than the equivalent US industrial motors from my experience.

 

[PCustoms]

nope it actually isnt. in-rush can be that high

Yes, of you kept reading I acknowledged that...

in-rush current lasts a few hundred millisecond, NOT 3-5secs

I know, that's why I said it was odd. Seems that if he has 78A inrush, but the inverter can do 90A for 3 seconds, it shouldn't have an issue.

 

[rlitman]

...Then the meter cannot measure in-rush properly. you need a meter with special circuitry in order to be able to properly measure in-rush current...

To be fair to the OP, there is no formal definition for inrush current, and many meters do capture what I would call I'' (read as "I double prime") under the guise of the min/max feature. That's how my Amprobe works. It mentions inrush in the instructions, but nowhere on the meter.

...Seems that if he has 78A inrush, but the inverter can do 90A for 3 seconds, it shouldn't have an issue.

Two things here.

First, it's not clear to me that his peak current was 78A. It could have been more if his multimeter was too slow (it could not have been less). In fact, it very likely was more than 90A, unless the machine was on an exceedingly long extension cord.

And second, an inverter stating it can handle 90A for 3 seconds is almost certainly talking about a resistive load with a unity power factor. Motor starting is nothing like that, especially when the motor has a flywheel on it (the impeller). Have a look at this: https://medium.com/@TimDolidze/ever...5?source=messageShare-6574bb928ca9-1669626606

and this:

...What are the letter codes and what would they tell us?

The NEMA code letter shows the ratio of locked rotor kVA per HP.

Electrical Motors - Locked Rotor Design Code Letters

NEMA locked rotor indicating code letters for electrical motors.

www.engineeringtoolbox.com

You can work backwards from that and the HP and known voltage to calculate LRA, which is the theoretical inrush current.

But I highly doubt HF is using NEMA motors on its dust collectors, so this is likely a dead end.

 

[WI/MI Border]

So you actually have grid power at this location?

Correct

 

[WI/MI Border]

...
no id like to see the nameplate.

It's up there in reply #19. That's all I found.

As far as the meter, its an inexpensive off brand clamp meter. I'll accept it isn't appropriate for accurate surge current but I hope it's close.

 

[PCustoms]

Correct

What is the goal of setting up the equipment to run off grid?

Seems like you might end up down an expensive rabbit hole to run optional equipment off grid

Also, I assume if you need a DC, there are other tools in use. Are those running off the inverter, or having similar issues?

 

[dave*99]

Here is one spec on the inverter...

The EG4 6000XP inverter features a 12kW (12,000W) surge capacity for up to 3.5 seconds to handle high in-rush currents, such as those from well pumps, AC units, or motors. It supports 6kW continuous output, managing heavy loads that might trip lesser inverters.

I believe that 12kW spec is @ 240V.

This was some interesting testing of that unit.

 

[WI/MI Border]

...

Two things here.

First, it's not clear to me that his peak current was 78A. It could have been more if his multimeter was too slow (it could not have been less). In fact, it very likely was more than 90A, unless the machine was on an exceedingly long extension cord.

In fact there was an extension cord on it initially. I removed it and replaced it with a two foot 12/3 ext cord. It is on its own 20a circuit fed with 12awg romex from the panel (about ten feet from its breaker). I tried again. It turns on with no problems on grid power. I switched the garage over to off-grid through the inverter and 32kWh battery (200a peak, 100a normal). It tried to start. The first try it tripped the inverter. I reset everything and tried one more time. Fail. I had to reset the inverter again.

...

But I highly doubt HF is using NEMA motors on its dust collectors, so this is likely a dead end.

Yep, it's worked hard for me for about ten years. I've been very satisfied with their 2015 version. The only disappointment is that the motor is not internally wired for 240v. I suspected that it was becoming tired, therefor my request on lumberjocks for some surge numbers from owners of the new Bauer dust collector (wired for 120v and 240v). So far all I have gotten is an AI response (suspect anyway) about various options I could do including adding a variable frequency drive, a soft start, replace the capacitor, and on and on. Helpful for some folks but not what I was asking for. But that is the forum world. I do cherish the helpful responses. I just asked for a 120v and 240v surge number to make a comparison. Hopefully I'll hear from two people with interest in what their dust collector draws.

Interesting discussions here. I'm always learning something. Thanks for all the responses.

 

[mike93lx]

It's up there in reply #19. That's all I found.

As far as the meter, its an inexpensive off brand clamp meter. I'll accept it isn't appropriate for accurate surge current but I hope it's close.

It's not accurate for surge.

 

[WI/MI Border]

I believe that 12kW spec is @ 240V.

This was some interesting testing of that unit.

Yep, that other Dave is very good at explaining solar stuff. I tend to defer to Will Prowse (YouTube or diysolarforum.com), Gavin Stone (Gavin Stone DIY Homestead) and Evan at Country View Solar. I began my home based solar adventures viewing many of these videos.

I have the 6000XP and it works great. I do have a lot to learn about its programming. A second 6000XP is on the way and will be wired and communicating with the first 6000XP and my 32kWh battery. Had I anticipated that I would almost immediately purchase a second 6000XP I would have gone with the two pack at a considerable savings or started with the EG4 12000 which would have saved even more. There's an active debate online about which approach is better; two 6Ks or one 12K or even the 18k. My goal is to take my home mostly off grid during normal load periods.

When the kids come home I can easily switch back to grid to keep things humming. Funny thought, I remember the commercial years ago where the dad comes to visit his kids at their newly purchased house and immediately runs through the entire house turning on lights. He's then shown with a satisfied look on his face standing on the front porch. Yeah, I've thought about doing that to my three kids with their first houses. ; )

To be clear, this is not a grid tied solar system. It has a split phase inverter (the 6000XP with 120v and 240v load capability) which can pass through grid power but does not back feed into the grid. So no utility permissions required (for now until the lawyers get busy). In my opinion this is a much better option for bringing your home/workshop into the future. My sister in Lincoln, NE installed a grid tied system several years ago on her home. It cost her a small fortune ($40k+ and I don't think she had the tax liability to fully take advantage of the tax credits). When she asked the contractor for a 20kWh battery option so she'd be up and running during a grid blackout the cost was an additional $25k for a 20kWh battery bank and switching gear. I created this system with two $1800 inverters, a big LiFePo4 battery (32kWh), $3250, 5.8kw of solar panels (used at about $1400) and probably about $750 of wire, conduit and hardware.

Off grid solar is changing quickly with these newer inverters and large, inexpensive batteries. If you haven't looked at solar for a few years it might be worth another look. We're no longer completely bound to the utilities for our power.

This thread started off asking about my dust collector. Please be aware that I will solve this problem eventually and it is not limiting my surge toward energy independence.

 

[dave*99]

I have a 2 HP Baileigh DC, not the same as yours but I took some measurements. It has a heavy impeller and takes forever to stop spinning when I turn it off. It is a 240V unit.
Inrush:

Running current

Motor type

 

[WI/MI Border]

I have a 2 HP Baileigh DC, not the same as yours but I took some measurements. It has a heavy impeller and takes forever to stop spinning when I turn it off. It is a 240V unit.
Inrush:

Running current

Motor type

That's very helpful. I would say that's very comparable.

At 240v and 64.2a inrush I'm going to conclude, probably immaturely, that my HF at 120v and ~78a inrush is probably OK. The Bauer is advertised as a 1.5hp and 11.5/5.7a running current (120v/240v respectively). But I know that tool makers and their claims for HP are suspect or the very least confusing : )