Hey Barry,
yes, it “may”, but it depends on how the VFD is set.
– Source: Omron MX2 User’s Manual, Page XIII
The behaviour of the VFD in case of a short power failure can be tweaked this way:
– Source: Omron MX2 User’s Manual, Page 121
– Source: Omron MX2 User’s Manual, Page 122
In my spindle manual, it says:
5.1 Electrical Risks
Ensure protection against overload or short circuit!
In the event of an overload - for example due to the motor shaft being jammed - or due to a short circuit, it must be ensured that the motor spindle is immediately disconnected from the voltage if the current exceeds the rated current of the motor spindle. Even if a phase fails, the motor spindle must be immediately disconnected from the voltage. This can be achieved with suitable motor protection switches or the appropriate parameterization of the frequency converter.(1) It is essential to ensure that the motor cannot start up automatically after the protective device has been triggered! Non-observance can result in an impermissibly high temperature rise in the motor spindle, which can lead to damage to the motor spindle and machine and even a fire hazard.
– Source: Mechatron HFS Series High-Frequency Spindle Operating Manual
- This is the reason why in a good VFD, you can adjust these settings.
But the spindle manual also says:
5.2 Risks from rotating parts and flying debris
Use machine encapsulation!
The high speed of tools up to 24,000 rpm poses a risk of injury from flying chips or the tool bursting. Fragments reach high flight speeds and can sometimes cause serious injuries. A separating protective device (machine encapsulation) must therefore be used that protects against flying chips and debris and also has a safety switch that disconnects the frequency converter or the motor spindle from the power supply on all poles as long as the encapsulation is not closed.
– Source: Mechatron HFS Series High-Frequency Spindle Operating Manual
That is why ISO 13849 Safety relays like the Omron G9SE (datasheet) have an input for a sensor switch on the door of the enclosure of a CNC machine, which signals him someone opened the door, which allows, if VFD is configured appropriately, to decelerate spindle immediately.