kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Isn't putting the motor into the circuit when the drive is already providing output a bigger issue with the drive then removing the motor from the drive while it running?
Local Start/Stop for VFD driven Motor
- Thread starter Electriman
- Start date
- Status
Aleman
Senior Member
- Location
- Southern Ca, USA
Maybe so because of the inrush current. Either way I don't think it's good to use disconnect switches to break loads.
As far as the original post goes, I wouldn't work on a motor if the power wasn't locked out. A HOA switched to off does
not make it safe to work on.
As far as the original post goes, I wouldn't work on a motor if the power wasn't locked out. A HOA switched to off does
not make it safe to work on.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
- Per the definition in Section 420.2 a VFD (actually an ASD, Art 430, Part X) is a controller. Technically, a hard contactor or switch isn't necessary; it only has to make or break the motor current. Hoe that is accomplished isn't specified.
- Section 430.108 requires every disconnecting means to meet the (fairly extensive) requirements of Sections 430.109 and 430.110. The Ampere Rating and Interrupting Capacity requirements are listed in Section 430.110.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
So is it OSHA or company policy, or old wives that require a visible contact break for some conditions?
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If contact break is required to be visible, you need a open style switch. Molded case circuit breakers/switches, and even snap switches generally do not have visible contacts and there are a lot of these used as disconnecting means.
- Status