Overhauling Two ABB Direct Current 1MW Extruder Motors

Customer: 

Pulp & Paper

Background: 

Motor Type:  Type: DMI400N ABB DC Motor 2290 Amp, 1200 RPM

The Solution: 

- JJ Loughran where asked to overhaul 2 NO:  3 Tonne ABB Mega Watt Direct Current Motors. Only a very limited number of companies would have the capability, personnel or equipment to carry out such complex repairs.

- The customer wanted an engineering company that would adhere to AEMT best practice methods for electric motor repairs and maintain motor efficiency and also a company that was certified to ISO 9001:14001 & 18001.

- JJ Loughran engineers where asked to carry out a full detailed mechanical and electrical inspection onsite of the 1 MW ABB DC motors they had not been overhauled since their original installation, this included inspecting brush gear, field coils, Interpoles, compensatory windings armature coils & commutators along with all required electrical tests.

- JJ Loughran briefed the customers as to the extent of the works that needed to be carried out and their respective costs.

- Once awarded the contract for the repair of the units, we removed the ABB DC motors from site. Once back in our main engineering facility, we carried out relevant inspection & tests before dismantling, labelling and cleaning of all parts as there had been large carbon build up inside the units.

- All dismantled parts were inspected and measured to ensure all critical dimensions were within tolerances; also checks were carried out to ensure there was no mechanical wear on the shaft, bearing housings or any other main components.

- Our engineers found excessive wear on the commutator. A good commutator  and current transfer are absolutely essential to successful performance and long life of direct current motors. A smooth commutator surface that runs true with respect to the bearing journals is essential for current transfer.

- As a result JJ Loughran had to machine the commutator in our state or the art workshop, controlling the process for turning and finishing, as well as protecting the commutator was essential. This allowed a quality finish for the brushes to connect  without arcing or vibration.

- As there had been a low insulation resistance, the stator was cleaned, stoved and varnished as required.

- The DC rotor was also balanced on JJ loughran’s latestIRD soft balancing machine to ISO 6.3 Grade. We Supplied and installed SKF Drive and Non- Drive end bearings as standard.

- We reassembled all parts and test run the DC Motor on our state of the art test bed complete with ABB 800 DC Drive. All results including rpm, vibration, torque, speed and amps were recorded.

- We then carried out a Full re-spray of the equipment to ABB original paint specification.

- The unit was then prepped for transport before being delivered back to customer site on time and within Budget.

 

Date

February 6,2016

Category