GE Power Controls

CMM Fuse Switch Units

CMM Fuse Switch Units

‘CMM’ Fuse Switch Units

CMM fuse switch units from GE PowerControls belong to a robust class of unitsthat provide large clearance and creepagedistances, despite having a smaller foot-print.This is achieved by a unique cassette designfor housing the fuse-links in a withdrawablefuse carrier. In fact the horizontal mounting offuse-links in the frame size 1 significantlyreduces the panel area, and overallcompactness gives the switchboard builderdrastic saving in panel size. Withdrawablefuse carrier also ensures TOTAL SAFETY,besides quick and easy replacement of thefuse-links. For reducing the down time theoption of using a replaceable carrier is alsoavailable. Thus flexibility, combined with highperformance and positive switching are thehallmarks of its unique and proven design.

CMM units are available in a wide range ofratings of 125A, 200A, 250A and 315A in oneframe size. 400A, 630A and 800A in anotherframe size, with a rated operational voltage of415V AC and 250V DC. Fixed & withdrawableversions are available.

Features

n All units are designed to comply with lS4064 - 1978. (Utilisation category AC23)

n Unique front-drive mechanism driving fusecarriage directly.

n Quick-make/Quick-break mechanism, withdouble break/pole.

n Fully-withdrawable, moving contactcarriage to facilitate quick-fuselinkreplacement and positive isolation.

n Front-drive incorporates safety doorinterlock facility.

n Self-aligning, spring-loaded silver-platedcaliper contacts.

n Fibre reinforced plastic moulds ensurehigh temperature and arc withstandcapabilities.

n Positive break feature ensuring switch canbe opened in the event of spring failure.

n Facility for fixing optional extras likeauxiliary switch and figure-type locks.

The Contact System

The CMM switch has a unique fixed-contactsystem comprising a set of fixed terminals inwhich self-aligning, floating spring loadedcaliper contacts are mounted. While one endof the caliper is secured firmly on the fixedcontact, the other end is open to receive themoving blade, thus ensuring a self-aligningfeature. This enables the switch to withstandhigh through-fault currents.

The Moving-Blade and FuseReplacement

The moving contact carriage housing theblades are fully withdrawable to enable quickfuse replacement and inspection of contactswithout use of tools. For this purpose, the redcam lever is to be raised against thespring pressure until the carriage is free. Thecarriage can now be withdrawn. For re-insertion, the carriage is pushed until thedrive engages.

Caution: The switch should not be operatedwithout the carriage in position.

Front-drive arrangement

A front-drive kit is supplied along with eachunit for fixing the handle assembly. Thehandle assembly can be fitted to the door byfastening the cowl with two M4 screws (seeFig.5) A door interlock comes along with thefront-drive kit to ensure that the door cannotbe opened when the switch is in ‘ON’condition. This interlock can be ‘Defeated’ byturning the slotted-bush about 300

anticlockwise.

Frame Size l Frame Size II

CMM125 CMM200 CMM250 CMM315 CMM400 CMM630 CMM800Nominal rating in Amps. 415V 50Hz 125 200 250 315 400 630 800Rating with solid copper links 200 315 400 400 630 800 1000Fused short-circuit current 50kA 80kA 80kA 80kA 80kA 80kA 80kARated short-time current for 1 sec. 2.5kA 5kA 5kA 10kA 20kA 25kA 25kA

Overload make/break make:for AC motor at457V and 0.37 PF 1000A 1600A 2000A 2000A 3200A 5040A 6400A

break:750A 1200A 1500A 1500A 2400A 3780A 4800A

Overload make/break capacityfor inductive circuits at 275 t/c 500A 800A 800A 800A 1600A 2400A 2400A0.15 sec.Terminal sizes 5 X 35 5 X 35 5 X 35 5 X 35 6.35 X 51 6.35X51 8 X 51Maximum size of links in mm. 6.35 x 5 6.35 x 25 6.35 x 25 6.35 x 25 6.35 x 51 6.35 x 51 6.35 x 51Recommended HBC TC/TF TC/TF TC/TF TC/TF TTS TTM/TLM TTM/TLMFuselinks TSDC TSDC TSDC TSDC TSMS TST/TSL TST/TSL

TSF TF TSF TSFTSK TSK

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CMM Fuse Switch Units

Fixed type - units Dimensional drawings in mm

With-drawable type units

Fig 1 CMM 125A - 315A

Fig 2 CMM 400A - 800A

Fig 3 Fig 4

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CMM Fuse Switch Units

Drilling Details

n CMM units are mounted using slots providedon the rear of the flanges.

n Door drilling details are shown by Ø

n Mounting details of the units are shown by Ø

Caution:

Ensure mechanism shaft engages fullywith the coupler for satisfactoryoperation

1 Interlock assembly2 Circlip3 Cowl4 Flat washer5 Spring washer6 Cheese head screw7 Coupler8 Rubber washer

Fig 5 CMM 400/630/800

Fig 5 - Front-drive assembly

10 Washer11 Handle12 Cheese head screw13 Spring washer14 Interlock spring15 Spiral Dowel Pin (4.8 x 3.21 g)16 Interlock bush17 Plug button

GE Power ControlsGE Power Controls India Private Limited1106/6, Balaji ComplexA.M. Industrial EstateGuruvebhavipalya, Hosur RoadBangalore-560 068Ph : +91 (080) 572 5140, 41, 42Fax : +91 (080) 572 4947

Note: Interlock defeat position and Dowel pin in ‘ON’ position shown in chain dotted lines.

CMM

- Ed

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