MG TR-EVO, Инструкция по эксплуатации, Страница: 12 / 24

The formula:
Pr
=
Cs
×
Lu
×
La

Sp
×
2
enables calculation of the maximum power Pr required by the heating element, where:
Cs = surface load in Watts per cm
2
. This value determines the speed the bar heats and assumes,
as seen above, a reference value of 30. Naturally, this value can be changed if higher speed
is required, or less power supply is available, or power that exceeds the maximum that can
be supplied by the controller.
Lu = heating element length in centimeters.
La = heating element width in centimeters.
Sp = heating element thickness in centimeters.
And its resistance R in ohm is:
ℜ=
Rs
×
Lu
/
100
where:
Rs = Specific resistance of the band in ohm/meter
These values are used to calculate the secondary voltage Vs of the transformer in volts according
to the formula:
Vs
=

Pr
×ℜ
The power of the transformer Pt must be calculated in Watts using the formula:
Pt
=
Pr
×
1,1
where 1.1 is a constant to compensate transformer losses.
In addition, we can calculate the peak current I in Amperes requested by the load which is worth:
I
=
Pr
Vs
"Hardware" configuration
Based on the current calculated, the switches must be configured on the temperature controller
and in particular: if the current is over 50A both switches should be closed, if the current is
between 25 and 50A switch 1 should be closed, if the current is between 11 and 25A the switches
should be left open.
For more detailed information, please compile and send the questionnaire in the
appendix. We will reply with a personalised application note for your application.
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