motor overloads
- Thread starter t-rhea
- Start date
- Status
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
Re: motor overloads
most (but maybe not all) vfds have built in overload protection that satisfies the NEC code with respect to motor overload protection.
you still need ground fault and SC protection.
most (but maybe not all) vfds have built in overload protection that satisfies the NEC code with respect to motor overload protection.
you still need ground fault and SC protection.
John Valdes
Senior Member
- Location
- SC.
- Occupation
- Retired Electrician
Yes, the VFD is an overload device within itself. However, I have seen overload relay's (non-adjustable) mounted on the load side of the VFD. I guess they wanted to be extra careful, since the VFD overload settings can be adjusted or tampered with by unauthorized personel. Very few customers set passwords for VFD's for all the obvious reasons.
wanderer20001us
Senior Member
Units that have an internal bypass for the VFD will have the 'extra' overloads to satisfy the overload requirements when in bypass mode.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
The VFDs I work on, AB Powerflex, have the overload setting done in the VFD software,and can be changed by the HIM (access keypad). The VFD won't allow the motor amperage to exceed the FLA of the motor.
Some operators are button pushers and will change the settings. Some won't.
Password protect the settings. I use a laptop and software to make the changes, as there are some 1,000 parameters that can be changed.
Some operators are button pushers and will change the settings. Some won't.
Password protect the settings. I use a laptop and software to make the changes, as there are some 1,000 parameters that can be changed.
John Valdes
Senior Member
- Location
- SC.
- Occupation
- Retired Electrician
"I use a laptop and software to make the changes, as there are some 1,000 parameters that can be changed".
Tom, Thats the reason I hate Allen Bradley VFD's
Tom, Thats the reason I hate Allen Bradley VFD's
FNCnca
Member
- Location
- Portola, CA / Reno, NV
But you only need about 10 params. to get one functioning. The extra 900+ gives you many pattern options. AB makes one fine VFD IMO. : )
racerdave3
Senior Member
- Location
- Western Massachusetts
FNCnca said:
I agree. I can remember many of the early VFD's in which you basically programmed in motor nameplate values along with a few other parameters and you were good to go. The new drives are so flexible and offer so many options for an array of different applications, that there are hundreds of parameters that most people never have to use. Sometimes you do come across a value that you want to change and it takes some time reading through the manual to find out where it actually is. All in all however, the AB drives are a great unit and truly top quality.
John Valdes
Senior Member
- Location
- SC.
- Occupation
- Retired Electrician
"AB makes one fine VFD IMO. : )"
Have you ever tried to repair an AB drive? If so, then you know what I am talking about.
Also, many if not most of the extra parameters available are rarely used. It's overkill.
I have worked with drives that have a 3 page parameter schedule and can do anything a AB drive can do. Why thumb through a 1/2" thick parameter book, when you can flip through 3 or 4 pages of settings.
If you think I am cutting down AB you are correct. But, I will admit they have the best customer support system in the industry.
Have you ever tried to repair an AB drive? If so, then you know what I am talking about.
Also, many if not most of the extra parameters available are rarely used. It's overkill.
I have worked with drives that have a 3 page parameter schedule and can do anything a AB drive can do. Why thumb through a 1/2" thick parameter book, when you can flip through 3 or 4 pages of settings.
If you think I am cutting down AB you are correct. But, I will admit they have the best customer support system in the industry.
- Status