TYPE M, WF GS AND K FRAMES WITH SLF, C AND ND MOUNTS

Vibration attenuation is dependent on base rigidity as well as isolator deflection. If a base becomes distorted because of weight distribution, belt pull or the torque introduced by a direct drive, the equipment will wear out more quickly and vibrate excessively because of the loss of alignment. Some of the symptoms are flapping belts, bouncing motor ends, noisy bearings and in extreme cases the fan wheel rubbing against the fan housing. Base resonance is another difficulty that can result from poor frame construction. If base members are light and long they will tend to resonate a low frequencies that may be sympathetic or close to the operating speeds of the fan or motor.

The vibration isolators supporting the base can only prevent the passage of a percentage of the vibratory energy above them. Thus good rigid bases that help to keep the equipment running with a minimum of vibration will result in more successful installations.

All of our bases may be used with Type SLF or C spring mountings, air springs or ND neoprene mounts depending on the degree of isolation required. In most cases height saving brackets are employed to limit elevations. It is always best to use as few mountings as possible to simplify adjustments and reduce the number of transmission points, therefore, the more rigid K and WF frames usually have only four mounts. All bases may be furnished with built-in motor slide rails.

	K frames are rigid floating concrete platforms. While the extra weight of the concrete mass does not reduce the vibration transmission it does reduce the operating amplitude, reaction to fan thrust and start and stop motion. The standard base consists of a structural channel or beam frame, height saving brackets, reinforcing rods welded in place and drilled steel members with sleeves welded below the holes to receive equipment anchor bolts where the anchor bolts fall in concrete locations. Our recommended depth criteria is 1/12th the longest dimension of the base. The frame is placed on roofing felt or plastic sheeting and filled with concrete. After the equipment is set, the mounting adjustment bolts both raise and level the base to the operating height.
	WF fan and motor bases are specifically designed for rigidity without concrete fill, as structural beam members form the rectangular perimeter framing. Our design criteria is a minimum beam depth of 1/10th the longest dimension of the base so that deeper, heavier members are automatically provided for larger equipment. GS bases are exceptionally heavy WF designs built to specific Government Specifications.
	M rectangular fan and motor bases are lightweight frames built to no specific criteria. Steel members may be light beams, angles or channels selected on the basis of the most economical useable design.

Complete Base Designation is the Frame plus the Mount i.e. KSL,  KND, WFC, etc.	Type SLF spring mounts are designed with extremely stable springs enabling them to resist the fan thrust without the use of supplementary housings.  Since there are no snubbers or shocks of any kind, isolation values approach the theoretical.  All mounts have acoustical pads and leveling bolts and need not be bolted down.  Static deflection up to 5.0" can be attained using stock springs.  Larger deflections can be provided if specified.	Type C spring mounts are designed so that neoprene sponge inserts limit movement during start and stop and prevent contact between the projections of the upper and lower semi-steel castings.  These inserts are designed for a minimum of damping in all directions.  This is a good design for engineers that prefer housed mountings.	Type ND neoprene mounts are designed for both high static deflections and simplified installations.  The rubber is loaded in both sheer and compression to provide the desirable straight line rubber-in-shear deflection curves as well as overload protection.  They are molded assemblies with skid resistant rubber ridged baseplates and need not be bolted to the floor on most installations.
K Form For Concrete	KSL Base 0.5-5.0" Defl	KC Base 0.5-1.0" Defl.	KND Base 0.2-0.5" Defl.
WF Structural Beam Frame	WFSL Base 0.5-5.0" Defl.	WFC Base 0.5-1.0" Defl.	WFND Base 02-0.5" Defl.
GS Government Specification Frame	GSSL Base 0.5-5.0" Defl.	- - - - -	GSND Base 0.2-0.5" Defl.
M Lightweight Frame	MSL Base 0.5 - 1.0" Defl. l.l - l.5" Defl. l.6 - 5.0" Defl.	MC Base 0.5 - 1.0" Defl. 1.1 - l1.5" Defl.	MND Base 0.2 - 0.5" Defl.