On Tuesday, 14 November 2017 14:19:52 UTC, T i m wrote:
On Tue, 14 Nov 2017 05:29:29 -0800 (PST), whisky-dave
wrote:
On Monday, 13 November 2017 17:21:04 UTC, T i m wrote:
On Mon, 13 Nov 2017 08:19:36 -0800 (PST), whisky-dave
wrote:
snip
It seems to trip out at about 98C (halfway up the last fin)
so drops to 700W at that point.
Right, it sounds to me like there is a 100 DegC upper limit stat and
only the heavy heater element is going though it.
So it's not realy a cut-out more like a cut-back.
Well, same thing in this case.
No it's not.
Aren't you the one who seemed to have no idea about any of this?
No I find out by testing not reading the data sheet.
But I can do both, all you can do is read the data sheet.
You do know it has both a cut-out and what I'm refering to as a cut-back.
I am describing the electrical device as being what it is, whilst you
are trying to conflate that and the function you (you believe) you see
it having.
I know what's happening vai experimentation.
You know what should happen hopefully via the data sheet.
So what does a cut-out do.
What it says. It's a thermal switch that cuts out (in this case) when
the temperature reaches a certain point and cuts back in again when
the temperature has dropped back to a certain (lower) point again
(just like a thermostat). You can get them that are wired in reverse
to control cooling fans etc.
So is it a cut-out or a thermostat, you seem to be saying tehy are the same.
Electrically, in this case the result of either 'activating' are the
exact same thing, eg, cutting off the flow of electricity through the
element(s).
But that's not what happens because when left on for 2 hours or more it seems when it cuts out the heater still consumes 700 watts.
This is what they call the Overheat protection it switches back to 700W.
So if this heater is left on it;s doen;t produce 2KW of heat it doesn't consume 2KW of electrical power it drops to 700W so effectively a 700W heater after two hours NOT a 2KW heater which is what most would assume as it's written on the box and the unit.
The cut-out is the Safety tip over switch, which acutally does cut out or off the electicity supply to the heater giving a reading of 0 Watts.
So you can't tell the differnce between those labels is that it. ?
Thermostat, cut-out, resettable fuse.
What? As you don't want to open a unit up and without recourse to a
wiring diagram you would (normally) have no idea which one had
operated if the unit had gone off (as they are all usually in series).
ITRW, if you adjust the main thermostat and it all comes back on, of
leave it to cool down a bit and it comes back on, then the thermal
fuse hasn't blown.
Not blown but reset but rarely happens it seems, the only sure way of getting the heater to again comnsume 2KW is to use a cold air blower (I have another fan heater) to blow cool air over the fins of the 2KW heater.
Yes, where the 'overheat protection' is provided by an overtemp /
thermal / cut-out / switch *and / plus* a one way (non-resettable),
thermal fuse.
As I thought you can;t tell teh difernce between these terms a thermostat is the same as a cut-out.
Are you now just trolling mate?
All I'm saying is a 2KW heater won't consume 2KW if yuo leave it on 'full' power it will drop to 700W so if you're calculating how much heat this unit will give out don't assume you'll always get 2KW because after 2 hours you won't it'll switch down to 700W.
I;m sorry you are finding this difficult to understand but it really isn't that difficult.
What measurements, most situations you decide what you want before taking measurements, because yuo buy based on teh specifications of the product.
Not in this case you shouldn't (tail wagging the dog) and John has
explained the process clearly enough elsewhere.
And that would fail in this case.
What you can measure (and it seems like you have been
able to do that bit) you can manage. ;-)
Yep, far better than those using theory.
But only as an 'observation'. You may now have a large quantity of
useless heaters on your hands.
and even more on there way it seems.
But I don't believe they are useless if you understand how they work.
You bought a car to tow a trailer but with no idea how big the trailer
was.
I know how big the trailer is I just didn't expect the car to go from say 2000 HP to 700 HP.
Does your car do that ?
would a 700 HP car take the same time to pull the trailer as a 2000 HP if you kept yuor foot down on the accelerator ?
I'd assume NOT but you seem to think it would, and I don't understand why.
You would have to decide that based on other factors that you haven't
yet covered (less I missed or forgot), like the need / usage,
environment (building type, thermal characteristics etc).
Yes and those were prettyy much fixed when it was built,
Indeed?
Yes just like you're trailer would most likely have a fixed weight.
so how would an engineer predict what sort of heater and what power would be required ?
See Johns replies for an answer on those.
doesnt give the answer and shows exactly what I predict a wrong result due to lack of actual knowledge.
Like, my mate used a waste oil burning space hearer (blown air) in his
garage but it got old and I think they banned them (or were going to
if not heavily updated etc). He got the gas board in and (long short),
much to my mates questioning, they fitted two blown air gas heaters
that were never going to be up to the job. The sales rep suggested he
set the timer to come on at say 6am so the place would be warm for
8am, completely ignoring that the first thing my mate typically did
was open up the end of the garage to move cars in and out (and in so
doing losing any heat). So, they eventually ripped out the new units
and fitted bigger ones that were up to the job.
Suppose he was told that 10KW heater would be required to do what he wanted and then on installign them, he found that after a while the 5x2KW were no longer 2KW but reduced in power to 700W, would that change any calculation,
Of course?
AT LAST the pennies dropped.
So can you show me where this is indicated on the web site. ?
PLease make sure you chek all links before answering.
http://cpc.farnell.com/pro-elec/pel0...ack/dp/HG00575
http://www.farnell.com/datasheets/2339828.pdf
http://www.easyflip.co.uk/CPC_Digita...gue/?page=1906