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Information
Helical geared motors
7
Information
Thermal power Pth [HP]
The table below lists the nominal thermal power values expressed in kW, in the following reference conditions:
• mounting position B3
•
continuous operation at input speed <= 1.800 rpm
• ambient temperature 77°F
• sea level altitude
•
air speed near the gear reducer >=38ips
•
absence of external radial and/or axial loads
Applying a power level not exceeding Pth
- at the above-mentioned reference conditions - guarantees the correct lubrication and efficient operation of the gear reducer.
NOTE: checking the thermal power of gear reducer versions with three reduction stages is unnecessary, as the thermal thresholds are not reached.
Application check
Except for continuous operating times below two (2) hours and successive pauses capable of bringing the gear reducer back to ambient temperature, for each application it is advisable to
verify the gear reducer’s thermal limit according to the following formula:
Pm < Pth * Fc * Fv*Fa
,
where:
Pm = input power to the gear reducer at 1.400 rpm (4-pole motors)
Pth = thermal power at the reference conditions (see above table)
Fc = ambient and operating temperature correction factor
Fv = ventilation correction factor
Fa = altitude correction factor
The correction factors refer to different operating conditions compared to the reference conditions, and are provided by the following ISO14179 tables:
Thermal power values at 1.750 rpm
Gear reducer
Pth [HP]
Gear reducer
Pth [HP]
HA31
/
H081
27
HA41
6.5
H101
38
HA51
9
H121
50
HA61
18
H032
5.6
HA32
5.5
H042
8
HA42
7.5
H052
9
HA52
12.5
H062
15
HA62
18.5
H082
24
H041
7.8
H102
36
H051
9.2
H122
42
H061
12
H142
50
(/)
Not available