Robuschi ROBOX SCREW Series, Инструкция по эксплуатации и техническому обслуживанию

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7.4 Operation with frequency converter
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Verify the electrcic and mechanic characteristics of the motor to select the suitable frequency converter
•
The frequency converter must be selected for a resistant torque constant with the speed
•
Fix the minimum frequency supply to avoid the compressor operation below the minimum speed
•
Fix the maximum frequency supply to avoid the compressor operation above the maximum speed
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The acceleration time of the motor from stand still to minimum speed must be > 5-6 seconds
•
The acceleration or deceleration of the motor during the normal operation must be <= 1Hz/s
•
In case of compressor speed below the 50% of the maximum speed check the lubrication oil pressure and set the reglation valve
if necessary
•
Do not activate on the frequency converter the function “FLYING RESTART CIRCUIT” to avoid any damage to the compressor
7.5 Operation with two pole motor
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Change from the high speed to low speed only after the motor is completly stopped
•
It is possible to change from the low speed to the high speed with the motor running
7.6.1 Safety relief valve (Versions /P and /C)
The safety relief valve installed on the ROBOX SCREW serves as protection of the discharge piping components and is set at the
maximum design pressure of the discharge silencer 3 barg
WARNING : The safety relief valve protect only the components of ROBOX SCREW and must not to be set at
a different pressure by the final customer.
WARNING : The safety relief valve is not a pressure regulation device.
If the circuit after the compressor operates at a pressure lower than 3 barg the final customer must install an
other safety relief valve after the check valve of ROBOX SCREW set at the relevant pressure
WARNING : Gas coming from the safety relief valve is hot and can hurt.
7.6.2 Safety vacuum relief valve (Version /V)
The pilot valve PSM, installed on the cover of VSM valve (see figure aside), opens the VSM valve during the unit
operation when the pressure of the plant is lower than the set value. To set the PSM valve : Unscrew the
locking screw 32 and act on the screw 31 until the VSM opens at the required vacuum grade within the limits
specified at paragraph 4.2
7.7 Oil pressure setting
The lubrication oil pressure must be in the range 1,1 – 2,5 barg.
Pressure valve A is designed to maintain the pressture within this range during the unit operation
Fig.5
32
31
A