Should I apply power before Kinetix drive is awake?

Hi All. I have a Kinetix 350 and a rotary TLY servo motor. I'm using the drive's STO function. AC power is supplied into the drive, passing through an "M1" contactor. It makes sense to me to keep that contactor open, preventing AC power to the drive, until the drive is awake.

Is that what you guys do too?

Unfortunately, I can't use "Axis1.DCBusUpStatus" to indicate that the drive is awake because it doesn't actually go high until the drive sees that AC power.

What else can I use in my logic to determine that the drive is fully awake?

There is no reason to not supply 3-phase, especially if aren't doing the STO input yet.

As far as checking for the drive to be online, FeedbackIntegrity should come up without having 3-phase as will SafeTorqueOffInhibit. Not sure about DriveEnableStatus.

So, it seems that the M1 contactor really has no function then. If power can be supplied to the drive anytime, without any risk of unintended motion or damage to the drive, then why not wire directly from your branch circuit protection to the drive?

FreeAtLast said:

So, it seems that the M1 contactor really has no function then. If power can be supplied to the drive anytime, without any risk of unintended motion or damage to the drive, then why not wire directly from your branch circuit protection to the drive?

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My understanding is that it really depends on the drive, and the desired PL. I've seen some drives (Yaskawa?) are only rated for the highest PL/SIL if they have an external contactor and it is under the control of the drive. Basically if the inbuilt STO function were to fail, the drive or the safety controller has the ability to pull the power to the drive as a last resort.

It may also be important in applications where no leakage current is desired on the output, if the motor needed to be regularly disconnected for example.

FreeAtLast said:

So, it seems that the M1 contactor really has no function then.

Click to expand...

Not with STO, a complete waste of time and money.