Keeping It Cool

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Last Updated on Thursday, 16 January 2014 22:17

DMU Kenlowe Fan Conversion

Introduction:

Having purchased our three car 117 DMU set in October 2011, it became all too obvious upon inspection that one of the fan radiator angle drives was not in a fit state to continue in service. Without a spare angle drive, enquiries to our friends at the Dean Forest DMU Group for a possible replacement revealed that they had instead replaced their angle drive with a modern Kenlowe fan unit. This offered a number of advantages including quieter running including reduced maintenance requirements and hopefully improved economy. A team from CDRL were quickly despatched to investigate the set up as fitted to a 108 to determine if this was a possible way forwards for a 117.

Having taken a number of photographs and having studied the electrical requirements in was quickly decided that we should convert No.1 engine on 51405 from the original angle drive arrangement to a Kenlowe fan.

As underframe space constraints were not such an issue on our 117 when compared to a 108 (see photograph above) it was decided to retain the fan housing in order to try and even out the airflow over the whole matrix. The following is an account of how we went about fitting a Kenlowe to a 117 DMU.

Mechanical Installation:

The first job is to remove the complete radiator and fan housing assembly from the DMU before the fan and fan housing can be unbolted from the radiator as in the photograph below:

From the back the castellated nut that retains the fan spindle in place can be accessed, as can be seen in the centre of the photograph below:

With the castellated nut removed, the fan and its spindle can then be drifted out of its bearings.

With the fan removed, an adaptor plate, cut from 1/16” steel plate, can then be fitted to the radiator housing. It will be noticed that the fan housing has already been drilled and tapped 5/16” BSF on its periphery, presumably for some sort of a guard fitted in previous BR service.

Picking up the existing holes and transferring them to the steel adaptor plate is something of a bind, but some careful work will allow the adaptor plate to be securely bolted to the fan housing. The photograph below details this work in progress.

With the adaptor plate temporarily bolted down, the 24 Volt 16” diameter Kenlowe fan can then be offered up and centred on the adaptor plate. Once the Kenlowe is in position, the four main bolt holes can then be carefully marked out. The Kenlowe is put aside to allow the four holes to be carefully drilled with a clearance drill to accept a 5/16” BSF (or metric equivalent if you really must!) bolt. The Kenlowe fan must then have its four locating holes also opened out for a 5/16” BSF clearance hole. Care needs to be exercised with this operation as the body of the Kenlowe is made of plastic.

All the components at this stage can then be trial fitted together to ensure that all will bolt down as required. Once happy that this can be done the adaptor plate needs to be removed for painting before final assembly can take place.

Once painted, the Kenlowe fan should be mounted on the adaptor plate first using four 5/16” BSF bolts. The heads of the bolts should be on the inside of the fan housing when assembled so that the four nyloc nuts are visible from the outside and thus can be checked at each exam for security. Once bolted up it is then possible to spot through from the outside with a 3/32” drill all of the peripheral locating holes. A self tapping screw can then be put in from inside face to ensure an air tight seal on the adaptor plate. The following photograph will hopefully make the above description a bit clearer:

The Kenlowe and adaptor can then be bolted to the fan housing using 5/16” BSF bolts (if your fan housing was already prepared by BR) with spring washers.

Note that the Nyloc nuts securing the Kenlowe fan to the adaptor plate are clearly viewed for inspection whilst the self tapping screws are now ‘invisible’. The ten bolts securing the adaptor plate to the fan housing are also clearly visible for inspection. The completed assembly can then be bolted back onto the radiator before returning them to the unit.

Electrical Installation:

Details of the electrical installation will be included in the near future.

Conclusion:

The Kenlowe conversion carried out on 51405 was completed before its first day in service on the GWSR in December 2011, since then the 117 unit has covered 11,399 miles in two years on 203 operating days. After the initial setting up of the thermostat no further action has been needed to keep the Kenlowe working. With two years of successful operation we now plan to extend the installation of Kenlowe fans to all our vehicles to replace some pretty tired angle drive units. With the installation of the Kenlowe fans on W55003 we hope to be able to establish whether there is an improvement in the fuel economy as we are already in possession of some good fuel economy data for this unit.