Danfoss iSave 50, Operating Manual

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Design Guide | APP and iSave overload protection
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4. Examples of VLT
overload limit settings
Below is two examples of how to calculate the
torque limit settings for an APP pump.
All calculations are made in the Danfoss HPP
calculation tool (please contact Danfoss HPP for
help).
Example 1:
Settings are made according to actual operating
pressure (see graph #2 in chapeter 2.1).
Example 2:
Settings are made according to maximum
allowable operating pressure (see graph #1 in
chapter 2.1)
• 77 m³/h and 60 barg max. operating pressure
• Design pressure 60 barg
√
Calculated operating torque: 934 Nm at 1,490
rpm and 60 barg.
√ Selected motor:
• 160 kW, 4 pole
• Efficiency: 95.8%
• Power factor (cosφ): 0.87
• Power supply: 400 [V]
• Rated speed: 1,490 rpm
• Max. current: 275 [A]
• Max. operating torque: 1,026 Nm
√ Calculate torque at 20% higher than
934 Nm = > 1,121 Nm
Parameter 4-16 setting = 107%
√ Calculate starting torque at 40% higher than
934 Nm = > 1,308 Nm
Parameter 4-18 setting = 121%
√ Calculated DC-hold: Parameter 2-00 is 49%
√ Selected delay before start
Parameter 1-71 is 4
(see chapter 5.3)
√ Trip delay torque limit:
Parameter 14-25 is 30 sec.
√ Calculated starting current: 334 [A]
√ Calculated operating current at 60 barg:
257 [A]
• 77 m³/h and 60 barg max. operating pressure
• Design pressure 80 barg
√
Calculated maximum operating torque:
1,246 Nm at 1,490 rpm and 80 barg.
√ Calculated operatin torque: 934 Nm at 1,490
rpm and 60 barg.
√ Selected motor:
• 200 kW, 4 pole
• Efficiency: 96%
• Power factor (cosφ): 0.88
• Power supply: 400 [V]
• Rated speed: 1,490 rpm
• Max. current: 340 [A]
• Max. operating torque: 1,282 Nm
√ Calculate torque at 20% higher than
934 Nm = > 1,121 Nm
Parameter 4-16 setting = 90%
√ Calculate starting torque at 40% higher than
934 Nm = > 1,308 Nm
Parameter 4-18 setting = 102%
√ Calculated DC-hold:
Parameter 2-00 is 47%
√ Selected delay before start
Parameter 1-71 is 4.5
√ Trip delay torque limit:
Parameter 14-25 is 30 sec.
√ Calculated starting current: 345 [A]
√ Calculated operating current at 60 barg:
271 [A]