Unox MINDMaps BAKERTOP, Service Manual

Page: 72 / 216

Speed regulation
The fan can spin in four different regular speeds and four pulse speeds. These speeds are equivalent in
terms of RPM, but in the pulse mode the fan spins only when the heating element are turned on.
Temperature and humidity measurements are the limiting factors for the fan speed as reported in table
13 . The power board applies a sinusoidal cut of the phase when the oven is running at speed 4 and it is
going to measure the climate conditions of the cooking chamber. The sinusoidal cutting is not applied
when the motor is running in normal conditions out of the humidity measurement.
table 13
Speed limits
Speed r1 r2
Sinusoidal
cutting
operation
(Lp
standard use
)*
Sinusoidal
cutting
measurement
(Lp
measurement
)**
rPM @ 100 °C
(212 °F) at 50Hz
range
4 0 0 1023 523/723 2750
30˚C– 260˚C/
86°F-500°F
3 0 1 1023 1023 2200
30˚C– 260˚C/
86°F-500°F
2 1 0 1023 1023 1500
30˚C– 230˚C/
86°F-446°F
1 1 1 1023 1023 900
90˚C– 200˚C/
194°F-392°F
At maximum speed and at 60 Hz, the motor can run at a maximum of 3300 RPM.
*LP
standard use
: Leading-edge phase in standard use, the table shows how many bits are activated during a
feeding cycle of the motor in working conditions.
**LP
measurement
: Leading-edge phase during the measurement; the measurement of the speed 4 during the
humidity measurement, is performed by activating 523 of the 1023 bits only (723 at 60 Hz)
fan speed vs Temperature
Temperature is the limiting factor for the ventilation as reported in table 14 .
These limitations are not used during the HUMIDITY CALIBRATION.
table 14
Temperature limits
Minimum Speed Temperature
V1 T
ch
> 90˚ C (194 °F) T
sp
< 200 ˚C (392 °F)
V2 T
ch
> 30 °C (86 °F) T
sp
< 230 °C (446 °F)
V3 T
ch
> 30 °C (86 °F) T
sp
= T
limit
V4 T
ch
> 30 °C (86 °F) T
sp
= T
limit
T
sp
: Set point temperature or, when working with the core probe, T
sp
is ∆T+120˚C.
T
ch
: Cooking chamber temperature.
T
limit
: 260 °C (500 °F), 300 °C (572 °F) for High Temperature ovens.
Timing
The ventilation works on a 100 seconds time basis pattern. At the end of this time the motor reverses the
sense of rotation with 3 exceptions:
■ Maximum steam, 100 % S TEAM.Maxi
TM
: the motor does not make the reversion in the range 70˚C (158°F) <
Tsp < 130˚C (266°F).
■ MAX SPEED N. INVERS. Parameter: if the set speed is equal or less than the value of this parameter, the
motor does not reverse the sense of rotation.
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