This page is split into the following sections, click the section name to jump directly to that section or simply scroll down:

Product Range
Standards and Certifications
Quality systems
Insulation systems
Specific Flame Proof Manufacturing Range
Testing
Standard Tests
Special Tests
Engineering

Product Range:

Manufacture and repair 10 kW – 500 kW AC and DC motors ≤ 1000 V Induction cage Slip ring induction Direct current EX d and EX n certified. (Zone 1 & Zone 2) Certification & Re-Certification to local and international standards. More than 100 existing new motor designs. Please also see specific manufacturing product range

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Standards and Certification:

Marthinusen and Coutts holds permits to manufacture and repair electric motors and electric enclosures according to SANS 60079-0, SANS 60079-1 (and SABS IEC) (Flame proof, EX d, Zone 1) as well as SANS 60079-0 and SANS 60079-15 (and SABS IEC) (Spark proof, EX n, Zone 2).

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Quality Systems:

Marthinusen and Coutts has the ISO 9001-2000 listing, which includes design and development for flame proof and spark proof motor and enclosures. This system is fully implemented throughout our flame proof processes to ensure customer requirements and local and international standards are complied with. Marthinusen and Coutts has a custom designed computerized MRP system (MotoMan™) to control and measure the production process throughout the manufacture or repair process. This includes procurement, stores, logistics, costing, estimating, customer feedback reports, failure reports, root cause analysis, etc.

Marthinsuen and Coutts strives to maintain World Class Manufacturing principles. Part of our ongoing improvement processes we have dedicated customer technical committees which continuously evaluate electric motor operation and failures in order to improve products and reduce total cost of ownership.

One of our strategic advantages is our ability to monitor on-site conditions in safe as well flame proof areas for instance underground coal mines. We can continuously monitor the following: Voltage, current, power, power factor, speed, vibration, humidity, temperature, etc. Thus improving our understanding of the customer’s plant and the running conditions of the equipment. This information can then be utilized to improve existing repairs as well as future upgrades to new motors.

All document systems and procedures are controlled through a business systems database.

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Insulation Systems:

Marthinusen and Coutts works closely with both local and international resin and insulation manufacturers to ensure that the best insulation systems are implemented to ensure the highest repair standards are maintained. This is another area that can significantly improve the motor’s reliability and dependability and ultimately reduce their Total Cost of Ownership.

We use high quality Grade 3 enamel coated high conductivity as well as superior inverter-grade copper wire. This inverter duty wire is not merely normal enamel coated wire with a thicker coating, but a specially designed enamel with Mica particles. This special insulation system is ideal for the flame proof environment where long trailing cables, VSD drives, etc. is the order of the day.

We fully utilise pure Nomex™ base slot insulation as well as top caps, phase insulation to ensure a high quality total insulation structure. On specific applications coils are also fully taped with pure Nomex™ or Mica insulation.

We have been successfully implemented the EpoSeal™ Epoxy based thixotropic VPI system. This system is effectively implemented in our custom designed PLC controlled VPI (Vacuum Pressure Impregnation) system. In contract with normal epoxy resins, this high build VPI system ensure phenomenal slot fill and overhang protection.

Furthermore we also utilise in our other VPI plant the state of the art (and Environmentally favourable) Dobecan™ polyester based VPI (Vacuum Pressure Impregnation) insulation system. This insulation system is specifically designed for DC, traction as well as high starting duty applications, because of it’s flexibility and resistance to temperature cycling.

Because of our high insulation specifications and quality standards we do not use the traditional “dip-and-bake” insulation system at all. The traditional dip and bake system has been proven far inferior in insulation, slot fill and voltage withstand properties when compared to our superior EpoSeal™ Epoxy based thixotropic VPI system.

Our temperature controlled curing ovens ensure that the insulation system is fully cured.

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Specific Flame Proof Manufacturing Range:

Marthinusen and Coutts manufactures various different specific flame proof motors. Here is a short list of some of the more common types:

And many others.

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Testing:

Our distributed reporting structure ensures that the testing department reports to the Engineering section and not to production. This is vital in ensuring that the highest possible engineering and testing standards are maintained.

Our test capabilities are thus structured around sound engineering principles. This culminates in many non-standard advanced tests being performed on a regular basis in order to ensure full compliance with local and international as well as customer specific standards.

Our flame proof test bay utilizes a customer designed state of the are computerized high speed and accuracy electronic recording system. This ensures a high degree of accuracy and confidence in the test results.

Standard tests includes:

• Winding Resistance using high accuracy four wire, high capacity resistance bridges.
• Insulation Resistance and Polarization Index measured on high accuracy, high capacity test equipment. (This equipment not only measures the insulation resistance value, but also displays the actual test voltage. This is critical since low capacity measurement equipment will give incorrect reasons on larger windings.)
• Surge Testing using state of the art Risatti test equipment. This ensures that any possible inter-turn or inter-phase shorts are detected prior to VPI or on final test. (Insulation Resistance in ineffective to detect impending inter-turn and inter-phase shorts.)
• No load testing at rated frequency. Values that can be recorded instantaneously and trended are:
  • Electrical input power (all three phases individually).
  • Power factor (all three phases individually).
  • Voltage (all three phases individually).
  • Current (all three phases individually).
  • Rotational speed.
  • Temperature of windings.
  • Temperature of bearings.
  • Temperature of casing or frame.
  • Temperature of air in and out.
  • Active power, reactive power and reactive power (all three phases individually).
• Locked rotor testing (also referred to as short circuit testing). Values that can be recorded instantaneously and trended are:
  • Electrical input power (all three phases individually).
  • Power factor (all three phases individually).
  • Voltage (all three phases individually).
  • Current (all three phases individually).
  • Rotational speed.
  • Temperature of windings.
  • Temperature of bearings.
  • Temperature of casing or frame.
  • Temperature of air in and out.
  • Active power, reactive power and reactive power (all three phases individually).
  • Locked rotor torque and current at various supply values.
  • AC Pressure testing. (Also known as the High Voltage Test

Special tests includes:

• Mechanical Pressure testing of frames. This special test ensure the highest level of safety standards on flame proof motors.
• Full mechanical load testing on two off Schenk water brake dynamometers, rated at 650 kW and 750 kW respectively. This type of testing can ensure the correctness of the repair, design modifications and new designs. Values that can be recorded instantaneously and trended are:
  • True mechanical output power.
  • Electrical input power (all three phases individually).
  • Efficiency.
  • Power factor (all three phases individually).
  • Voltage (all three phases individually).
  • Current (all three phases individually).
  • Output torque.
  • Rotational speed (and slip).
  • Temperature of windings.
  • Temperature of bearings.
  • Temperature of casing or frame.
  • Temperature of air in and out.
  • Active power, reactive power and reactive power (all three phases individually).
• Maximum locked rotor testing (also referred to as maximum short circuit testing). This test evaluates the compliance with various local, international and customer specific standard regarding permissible locked rotor times. Values that can be recorded instantaneously and trended are:
  • Electrical input power (all three phases individually).
  • Power factor (all three phases individually).
  • Voltage (all three phases individually).
  • Current (all three phases individually).
  • Rotational speed (and slip).
  • Temperature of windings.
  • Temperature of bearings.
  • Temperature of casing or frame.
  • Temperature of air in and out.
  • Active power, reactive power and reactive power (all three phases individually).
  • Locked rotor torque and current at various supply values.
  • Time.
• Pull-out torque testing (also referred to as maximum overload testing). This test evaluates the compliance with various local, international and customer specific standard regarding permissible overload or pull-out torque. Values that can be recorded instantaneously and trended are:
  • Electrical input power (all three phases individually).
  • Power factor (all three phases individually).
  • Voltage (all three phases individually).
  • Current (all three phases individually).
  • Rotational speed (and slip).
  • Temperature of windings.
  • Temperature of bearings.
  • Temperature of casing or frame.
  • Temperature of air in and out.
  • Active power, reactive power and reactive power (all three phases individually).
  • Torque.
  • Time.
  • Rotational Speed (and slip).

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Engineering:

Marthinusen and Coutts employ some of the leading electrical and mechanical design experts in the flame proof market. These people are key to the development of superior new flame proof motors in order to improve efficiencies, power factor, quality, reliability and ultimately to reduce the customers Total Cost of Ownership.

These engineering expertise work closely with some of the best production artisans with many years experience in electric motor repair and manufacture. This ensures that every engineering design be executed to the letter. Such perfect work ethics is critical to the correct repair and manufacture of flame proof motors. There is no room for any compromise on quality or even the tight tolerances to which we work to. Critical in the process is the interaction with the quality department. Through independent inspectors and assessors it is ensured that no compromise is made on the strict repair standard, because on flame proof motor repair and manufacture – more so than on motors for safe locations, mistakes and compromises can results in huge production losses and injuries.

Marthinusen and Coutts have successfully upgraded the protection of safe motors (IP55) up to non-sparing motors (Zone 2). This service we offer to our customers on a case by case basis.

Our engineering department utilises the latest 3D CAD design software. This software enable us to soft-prototype, i.e. run mechanical fitting models without manufacturing samples. This greatly reduces research and development costs as well as time-to-market. Furthermore the overall quality of the design models if far superior to conventional 2D based CAD designs.

Electrical design are check by graduated electrical engineers on custom written design software. These design software can be used to thoroughly check each repair as well as every new motor manufacture. Amongst others, the following design parameters can be checked:

• Current: Full load, other partial load points as well as no load.
• Rotational Speed and slip: Full load, other partial load points as well as no load.
• Losses: Full load, other partial load points as well as no load.
• Efficiency: Full load, other partial load points as well as no load.
• Power Factor: Full load, other partial load points as well as no load.
• Temperature rise: Full load as well as other partial load points.
• Bearing life.
• Bearing re-greasing interval.
• Critical speed.
• Run-up times.
• Stall time.
• Number of starts from cold and hot.
• Current density.
• Flux densities.
• Starting current.
• Starting torque.
• Pull-out torque.
• Pull-up torque.
• Torque vs. Speed curve.
• Current vs. Speed curve.
• Efficiency and Power Factor vs. Load curve.

Our design capabilities include the design of new motors as well as upgrading, modifying, improving and upgrading of existing design. Improvements include:

• Efficiency.
• Power Factor.
• Increase power output ratings.
• Electrical and mechanical design.
• Bearings.
• Cooling.
• Speed.
• Etc.

In addition to the standard electric motor design, we can also assist with special application designs such as:

• High starting torque designs.
• Low starting current designs.
• Double cage rotor designs.
• Slip ring induction designs (Wound rotor designs).
• Etc.

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