I have seen a lot of people using these and having a good experience. I have had 3 in just over a month the first one lasted around a month. It probably had 15-20 hours. The longest it was run was around 4 hours. They all had same symptoms. 1 second there working and then there’s a slight change in sound like a quiet pulsing. I’m not sure if the dust is getting by the filter and into the motor or the flap if it uses one. I assume the motor is sealed. The filter looks brand new and the bag only had a few inches in it. The second one was only used 2 times.
When it failed, I was cleaning up dust on the floor from a few 2x4’s. The third only lasted a few minutes. I was vacuuming up aluminum chips that were on the rails and in the T-slots and the same thing happened. My shop vac is 20 years old and works, but noisy.
There is a thread on Reddit about the same thing.
Seems Dewalt replaces the power head.
They ask about the length of an extension cord being used.
Hmm. I have had mine for over a year and not had any trouble. Do you have the 12 gallon or the 9 gallon model? I opted for the larger as it had the bigger hose.
I have the 9 gallon. I didn’t need more capacity, but didn’t see the difference it the hose. I thought the hose seemed like an odd size. I 3d printed an adapter to sweepy.
Right. It was t about capacity for me since I have the cyclone in front but I wanted the hose size and associated throughput.
I wonder if the issue you are having is localized to the 9gal unit.
So I did experiments with my Stealthsonic to see how it would handle being on a motor speed controller. One of which was to attach a temp probe to the motor. To do so I had to take the thing apart so I am familiar with its inner workings. The 12G model has vents on the sides where the clips that hold the motor head to the bucket are for taking in air to cool the motor.
They are a bit hard to see in the picture, but if you zoom in you will. This is for when you are sucking up stuff like water or when the hose gets blocked the motor can remain cool. As such it is possible that the the motor head could suck in dust from your shop bypassing the bag and filter.
Shopvacs, for as long as I’ve used them & been taking them apart(25+yrs), are designed with a separate airflow stream to cool the motor. The vacuum air stream never touches the motor. This allows for them to be used to suck up water & crap as it won’t short out the motor or cause it to sieze up.
Fine wood dust hanging in the air doesn’t really affect the motor - too turbulent when it’s running. Though I will say that drywall dust can coat the motor & inside the cowling pretty good.
Most times when a shopvac fails while running, it’s due to bad bearings siezing up & causing the motor to overheat & burn out the windings somewhere.
Other times it can be the power switch no longer makes proper contact - so you try to turn it on & nothing happens. The switches are usually pretty easy to replace as they are a common type & electrical rating.
Dewalt is an old tool company. They are part of a conglomeration now are making a lot of tools like log splitters, tool sets etc… All of it is made in China and Chinese supply chain can be quite spotty. Whirlpool set up a factory in China to make dishwashers. The engineers with Whirlpool went over and got the production line set up and the parts set up. After the engineers left the factory started sourcing their parts from cheaper sources and the Whirlpool dishwashers starting having their doors fall off. Whirlpool investigated and found that the factory they were contracting with were changing to inferior parts to make them more money. Whirlpool pulled the dishwasher lines back to the US. Sometimes even good parts are made wrong and you get batches of them that are bad. Maybe that is what is happening with the Dewalt Stealthsonic vacs. Or as @CthulhuLabs suggested the 9 gal has a motor cooling design flaw. If it is new talk to Dewalt support and get it replaced. It is always a hassle to deal with any support and then wait around for a replacement.
The conversations I read were about insufficient voltage due to extension cords.
I guess motors don’t like low voltage ?
There seems to be a thermal fuse that let’s go.
If the voltage drop across an extension cord is too great, the motor pulls more current to compensate. More current means more heat generated in the motor windings which can lead to burn out. So the thermal fuse is to keep that from happening.
There is a voltage drop along a long extension cord. How much that is debatable. However how many shop vacs are run on extensions in the history of shop vacs? Likely the answer is most of them. So the extension cord could be the culprit but the real problem is an engineering one if that is the case. It is wise to plug directly into a plug but frankly a shop vac is not usually used near an outlet because it is used to clean up. So if you cannot use an extension cord on a shop vac there is a problem from Dewalt. That does not help if your vac is not working but if Dewalt is telling you the problem is an extension cord sounds like BS. That would be a CYA for Dewalt.
Voltage drop per se should only lead to a lower RPM and lower amperage draw from the motor. However, if there is a speed controller (or brushless controller) attempting to maintain motor RPM then the voltage drop would cause significantly greater concern and may trip protection circuitry.
“Voltage drop per se should only lead to a lower RPM and lower amperage draw from the motor.”
Incorrect, if you drop the voltage the amperage has to go up for the equation work.
Undervoltage kills more appliances than most consumers know. I have a step up transformer for my camper to prevent high current draw on the A/C with lowering voltage in campgrounds. If voltage drops to 109v’s the transformer swaps coils and increases the voltage to 122v’s. This prevents burning up the A/C.
Good to know. Thank you. I wonder if load factor is the cause since motors are doing work not spinning in free air.
Yes, it absolutely does. As mentioned above, some motors have separate air flow for cooling the stator and some have the supply of air from the impeller itself which can provide contaminants into the stator which reduces heat transfer rate and causes the breakdown of windings etc and ultimately a shorter life span.
I gather you meant “for the equation TO work”? What equation are you referring to? It can’t be Ohm’s Law: V = IR which, assuming resistance through the circuit remains constant, implies I should decrease if V decreases.
From an online resource.
What is under voltage?
Undervoltage occurs when the average voltage of a power system drops below the nominal voltage, usually (around 230v in the UK, 220v in Europe and 110v for US markets). When devices are forced to operate on reduced power levels, they draw higher currents which means the components inside the appliance will be forced to work harder which, over time, damages the equipment. For example, the wiring inside equipment that have motors such as fridges suffer substantial wear and tear. Forcing equipment to work in these conditions for a prolonged period reduces their life drastically which can lead to permanent failure.
From my previous career we had specific low and undervoltage motor trips to prevent higher running current which led to stator winding/insulation degradation due to increased heat from higher amps. This condition also led to rotor bar cracking.
If you put a clamp-on meter on your vacuum and start it you will see the amps increase 5-8 times the normal running current (some sources say 5-6x and 6-8x locked rotor) and the voltage drop until the motor gets up to rated speed. Then voltage comes back up and amps back down.
It’s been 50 years since I took a motors class, but there are different types of motors. Synchronous motors will try to draw more current with lower voltage and can overheat (your tablesaw probably has a synchronous motor); universal motors will draw less current and run slower with less voltage (that’s how speed controls for most routers work). Brushless motors (most spindles) will depend on controller design.
You are correct, I’m not an electrical engineer by trade. There are more variables as you state above, I may be confusing synchronous motors with the universal. Thanks for reminding me.
I did not mean to derail the post or provide any incorrect information.
Having taken a StealthSonic apart it is a universal motor.
I think the more likely problem with reduced voltage from an extension cord is that it also reduces torque. The reduced torque could lead to the motor stalling and thus overheating.