Electronically controled motor

[Simon35]

The inverters must have been fitted for a reason. What was the reason?

the old motors had independant inverters, the new motors come as a package with inverters mounted on them, these were fitted by another company

If you get them set up properly you dont need to change your mcb, and you certainly don't need a motor rated one.

It was yet another company setting them up, that said they want them changed and they are setting them up nationwide and also WILO technical dept have now said they need to be motor rated mcb's

Have the pumps actually been run, and the C16 breakers are tripping? If they are tripping, is that on powering up the inverter or on starting the motor, or after the motor has been running a while?

BTW, in your first post you said the old motors were started by contactors, and in this one you have said inverters?

Just out of curiosity, I had a look at the manual from WILO website for these pumps. Page 71 suggests either 25A fuses, or
Miniature circuit breaker tripping characteristic: B
• Overload: 1.13-1.45 x Inominal
• Short circuit: 3-5 x Inominal

No mention of type D breakers....

 

[333rocky333]

The inverters
Have the pumps actually been run, and the C16 breakers are tripping? If they are tripping, is that on powering up the inverter or on starting the motor, or after the motor has been running a while?

Not as far as I know, the company that sets them up said that they will,when they run at full demand, thats all we know for now.

BTW, in your first post you said the old motors were started by contactors, and in this one you have said inverters?

That was just a query, regarding if, motors with an invertor need overloads, as im not used to inverters, in the past meant "as in previous jobs" where motors were old school , the overloads were tagged on the contactors

In the past the old pumps at this site were via inverters in a seperate sarel box, the original switches and indicaters are now defunct on the H+V panel and the new wilo pump supplies are direct from the mcbs, hence the query about need of overloads, i assume the C16's ran the other pumps ok, size of them motors was not known

Just out of curiosity, I had a look at the manual from WILO website for these pumps. Page 71 suggests either 25A fuses, or
Miniature circuit breaker tripping characteristic: B
• Overload: 1.13-1.45 x Inominal
• Short circuit: 3-5 x Inominal

No mention of type D breakers.

Thanks, as said I have no access to ZIP files at home, I wil try and check that tomorrow, it was the so called Wilo tech helpdesk that said they needed motor rated breakers, but we are gonna get a second opinion asap.

 

[333rocky333]

Just out of curiosity, I had a look at the manual from WILO website for these pumps. Page 71 .

Simon, im struggling to find that, help please

 

[Simon35]

Just out of curiosity, I had a look at the manual from WILO website for these pumps. Page 71 .

Simon, im struggling to find that, help please

No problem, watch this space tomorrow.....I'll post a link.

 

[ericmark]

Where you need overload protection these

don't need connecting to a contactor and double as a MCB but with an inverter built in there is no need for overload protection so simple MCB is good enough. Most inverters can be set as to ramp up and ramp down and in the main your only worried about run amps there is no real start load, but you can set a fast ramp up which would give a start load so it does depend how the inverter is set. So in the main read motor label and select a MCB just above run amps no need for C or D rated. The connection between inverter and motor should in most cases never be broken. Any open circuit between inverter and motor can take out the inverter.

SWF did a range of motors with the inverter and ASii control built in and even in some cases gear box and brake and they were very good. I was able to stop and start the motor driving a harmonic arm very precisely which just did not work with independent units so I would say the same is true with pumps. I remember many years ago 1970's working for SLD pumps and the pride of the fleet was a hydraulic powered submersible pump driven from a swash plate unit as it could run at a speed to match the viscosity of the liquid being pumped. This can now be done with electric pumps using inverters the rate of flow can be altered to match conditions. Often linked to the PLC it can do what yesterday we only dreamed of.

The inverter alters both frequency and voltage to match allowing a 50Hz motor to run maybe as low as 10Hz to as much as 100Hz so giving a very versatile control, the soft start does as suggested it replaces any star/delta but it does not allow different running speeds. The inverter first turns the AC to DC then charges capacitors and turns it back to AC. As a result inverters don't NEED a three phase supply to run a three phase motor this has caused problems as often when running on a single phase supply the motor is run delta where with a three phase supply same motor is run star.

Be it PLC control or inverters when I first came across them they sacred the hell out of me. But today it is standard and more and more inverter control is used, even in the home, my washing machine, freezer, and fridge/freezer are all powered by three phase motors and inverters.

 

[Simon35]

http://productfinder.wilo.com/en/GB/productrange/000000220003aad200010023/fc_range_downloads

is where I downloaded the installation and operating instructions zip file from.