what are the pro's and cons of plugging power tools and a portable welder designed for 240v into a 220v supply as far as potential damage to said tools may cause(if any).id particually like to hear from others who have had experience or info from sparkys rather than guess answers.Thanks to all in advance who have taken the time effort to answer my query.
tmenz,
Jan 18, 12:07pm
There shouldn't be any damage but the tools won't work as efficiently. The power will be down by about 15~20% depending on the particular type of tool. If it was the other way around, then there would be real possibiliies of overheating and burnout - both from over-voltage and under-frequency!
sr2,
Jan 18, 1:49pm
Sorry but not a good answer, many tools will attempt to pull more amps when they are running on a lower than designed for voltage.Sounds like a recipe for a smoke up!
kwaka5,
Jan 18, 2:23pm
Can i ask what the supply is from.
ralphdog1,
Jan 18, 2:45pm
tmenz is correct, with the added comment that if you are hammering the shite out of something the chance of letting the smoke out is a bit greater but as long as you are not abusing them you will be fine.
tonyrockyhorror,
Jan 18, 3:21pm
Ohms law tends to disagree with an electrical device 'pulling' more current when supplied with a lower voltage.
tmenz,
Jan 18, 3:34pm
Sounds like the OP might be transferring NZ or UK single phase tools to somewhere like the US or Canada where they have 60Hz 127v 1Ø or 220v 3Ø supplies. Some houses are equipped with 2 phases which allow 220v appliances to be used.
wasser61,
Jan 18, 3:54pm
Power is calculated simply as Volts x Amps = Watts Therefore if the voltage is lower the Amperage (current) will go higher)
tmenz,
Jan 18, 4:30pm
Incorrect. The power is not a constant. The impedance of the tool is the constant, provided it is not overloaded. A sander (for example) that is rated at 480 W at 240 V will have an impedance at its normal rated speed and workload of V²/W =240²/480 = 120 ?
tonyrockyhorror,
Jan 18, 5:12pm
Saved me a whole lot of typing!
sr2,
Jan 18, 6:35pm
It's a very common occurrence on amplifiers when the power supply sags.
tmenz,
Jan 18, 7:39pm
If a device, (usually a box of electronics, computer, amplifier, cellphone charger or the like), is fitted with a switchmode regulated power supply, then the PSU is usually designed to output a constant voltage regardless of the input voltage (within specified limits) or load current. It tends to act as a 'constant power' unit under varying input voltage conditions, which can draw more current from the input to make up for lack of voltage. (Conversely it will draw less current if the voltage rises above nominal). The extra current multiplied by the lesser voltage tends to equate to a constant power. (assuming a constant power output from the supply). SuchPSUs will not go into meltdown or 'smoke escape' mode when overloaded - they are usually well protected against anomalous inputs or loads, either by fuses/breakers or electronic shutdown circuits.
Some modern power tools with variable speed control have basic regulator circuits built in that will attempt to maintain speed and power within a fairly limited range of input voltages - these tools (usually the more expensive ones) can draw more or less current to cope with input voltage fluctuations. However, these regulator circuits are usually self-limiting and won't allow the power draw to get excessive to the point of 'smoke release'.
The cheaper tools with speed control don't usually have the luxury of regulation and it is up to the user to ensure that overload doesn't occur!
tmenz,
Jan 18, 7:43pm
They'll be fitted with switchmode power supplies that act as 'constant power' devices. (i.e. variable impedance).
taipan4,
Jan 18, 8:02pm
no mention made of any possible effects of the increase in Hz 10 hz equals 20%which would result in rotating equipment runnung faster & drawing more current.!
sr2,
Jan 18, 8:35pm
Good point, I hadn't considered that.
sr2,
Jan 18, 8:38pm
It happens with traditional transformer/ rectifier power supplies as well.
ralphdog1,
Jan 18, 8:50pm
Rotating faster does not inherently mean more current, as the faster speed will generate more back EMF to control the current drawn.
tmenz,
Jan 19, 7:47am
Applying 60Hz to a 50Hz induction motor will tend to make it run faster if it is developing enough power to do so - certainly if it's not loaded, but probably not if it's loaded to it's 50Hz rated load.
At the higher frequency, the impedance of the motor will increase so the current draw will be proportionately less so the power available will be derated. For a 240 V, 480 W, 50 Hz motor, the power capability will be reduced to approximately 400 W at 60 Hz. If the input voltage is reduced to 220 V as well, the power rating will reduce to about 340 W.
The speed of an 'universal' motor, such as is found in the typical power tool, is not dictated by the frequency. The impedance will rise and the current draw and power available will fall, as above, if 60Hz is applied, but the motor will not try to run at 'synchronous' speed and will probably run slower even when unloaded.
studio1,
Jan 19, 1:44pm
We still don't know where this supposed '220 volt' supply is, or whether the tools in question are indeed rated at 240 volts. I find it common these days for people to rattle off the figure of '240 volts' whenever they refer to the mains in this country and it's quite annoying. We have NEVER had 240 volts here as a standard measure. If the tools are in fact rated for 240 volts, they've probably come from the UK.
tmenz,
Jan 19, 2:11pm
Some of my power tools are labelled 230V, some 230~240V and some 240V. Most 50Hz only but a couple labelled 50/60Hz. I guess it's where they're sourced from that determines the design figure. Possibly Australia or UK. If they're designed for 240V then they need to be slightly derated when running on our 230V system, but in most cases it's purely academic. The voltage at my house is usually about 233~237 V so it's comforting to know my 240V tools aren't being overstressed.
intrade,
Jan 19, 2:27pm
The hz is a problem incorrect hz will destroy tools you can even go as low as 180volt and no damage will occure but hz incorrect damages the tools 10hz maybe tolerated. the hz is tetermened by the rotaitons of a generator like my deutz is running 1500rpm 50hz
tmenz,
Jan 19, 2:51pm
Tools made for 50Hz should not be harmed by being used at 60 Hz, but tools made for 60Hz may run poorly and overheat if used on 50Hz. This is because the higher frequency motors need less copper and iron in them to run efficiently without saturating. When 50Hz is applied to them the iron cores can saturate and the copper windings may not have enough inductive impedance and can draw too much current, thus overheating and reaching 'smoke release' status.
nixs,
Jun 15, 3:20pm
How can i supply 220v/60hz power to a Floating Dock floating 200mts away from the shore,we use 240 volt/50hz here in Fiji.They have 2 gen set thats locked at 220v and a freq of 60hz.
They need their supply locked at 220v/60hz nothing more or less.
Thanks
Since the public registrations are closed, you must have an invite from a current member to be able to register and post in this thread.
Have an account? Login here.