Heaters with "electronic" thermostat

[[email protected]]

I have seen a huge rise of oilfilled electric heaters with "electronic"
regulation in europe lately. My guess is that those regulators work just like
ordinary lightbulb dimmers, althought with higher power.
(assumed triac control with forward phase regulation)
Light dimmers will distort the powergrid some, but heaters are a lot more
powerfull and with rapidly increasing numbers they are likely to cause more
EMI etc.. Is there anything in the workings that will make them outlawed?
Will the powergrid in residential areas become a royal source of noise?
(and overheated motors, broken computers etc..)

 

[John Larkin]

On 16 Nov 2004 22:49:45 GMT,

I have seen a huge rise of oilfilled electric heaters with "electronic"
regulation in europe lately. My guess is that those regulators work just like
ordinary lightbulb dimmers, althought with higher power.
(assumed triac control with forward phase regulation)
Light dimmers will distort the powergrid some, but heaters are a lot more
powerfull and with rapidly increasing numbers they are likely to cause more
EMI etc.. Is there anything in the workings that will make them outlawed?
Will the powergrid in residential areas become a royal source of noise?
(and overheated motors, broken computers etc..)

Heaters often use zero-crossing cycle bursts, which aren't as noisy
and presumably have less nasty effects on the power grid as compared
to phase control. Could make the lights flicker, though.

I had a customer once who wanted to know the power factor of a
zero-crossing triac'd waveform. The concept is nearly meaningless.

John

 

[Pooh Bear]

On 16 Nov 2004 22:49:45 GMT,


Heaters often use zero-crossing cycle bursts, which aren't as noisy
and presumably have less nasty effects on the power grid as compared
to phase control. Could make the lights flicker, though.

There are IEC derived standards ( ENs ) that all products marketed in Europe are
required to meet under the EMC legislation - including flicker regs - and indeed
harmonics ( if it's phase controlled ).

I had a customer once who wanted to know the power factor of a
zero-crossing triac'd waveform. The concept is nearly meaningless.

Lol !

Graham

 

[Kryten]

I have seen a huge rise of oilfilled electric heaters with "electronic"
regulation in Europe lately. My guess is that those regulators work just
like
ordinary lightbulb dimmers, although with higher power.
(assumed triac control with forward phase regulation)
Light dimmers will distort the powergrid some, but heaters are a lot more
powerful and with rapidly increasing numbers they are likely to cause more
EMI etc.. Is there anything in the workings that will make them outlawed?
Will the powergrid in residential areas become a royal source of noise?
(and overheated motors, broken computers etc..)

If it really is a thermostat, it will initially switch the heater full on
until the room temperature reaches an upper limit, then switch off. When the
room cools below a lower limit, it switches on again.

This cycling takes in the order of minutes, so the switching spikes are not
that frequent.

Lightbulb dimmers are power choppers - they switch off part of every AC
cycle, 50 or 60 times a second. Moreover, this is a steep switch on/off,
hence harmonics that need filtering out.

I doubt the heaters will be more of a problem than they are when operated by
a simple switch.

 

[Fred Bloggs]

I have seen a huge rise of oilfilled electric heaters with "electronic"
regulation in europe lately. My guess is that those regulators work just like
ordinary lightbulb dimmers, althought with higher power.

Nah- ON/OFF control all the way- there is nothing proportional- and
"electronic" most likely refers to a thermistor temperature sensor with
setting comparator driving a high power miniaturized sealed relay which
throws line power onto the heating element. The whole purpose of the
*oil* is add a thermal mass for smoothing of the temperature response-
who in their right minds would then make the voltage drive proportional.

 

[Fred Bloggs]

Time proportioning is pretty common in temperature control and adds
little to the cost. It has very little downside if the output device
can handle the number of operations.


Best regards,
Spehro Pefhany

I thought he was talking about voltage proportion with that phase angle
control of the line voltage.

 

[Spehro Pefhany]

Nah- ON/OFF control all the way- there is nothing proportional- and
"electronic" most likely refers to a thermistor temperature sensor with
setting comparator driving a high power miniaturized sealed relay which
throws line power onto the heating element. The whole purpose of the
*oil* is add a thermal mass for smoothing of the temperature response-
who in their right minds would then make the voltage drive proportional.

Time proportioning is pretty common in temperature control and adds
little to the cost. It has very little downside if the output device
can handle the number of operations.


Best regards,
Spehro Pefhany

 

[Spehro Pefhany]

I thought he was talking about voltage proportion with that phase angle
control of the line voltage.

I'm sure he was.

Actually you'd probably want to miminize the switching in a
residential setting- lights flickering every few minutes is a lot less
distracting than a couple of times a minute.


Best regards,
Spehro Pefhany