Just to recap, we were discussing if the VFD DC Bus would allow to slow down / stop the hoist load via the available regenerative current in a power shutdown scenario, before the static brake could tackle the runaway load.
The static mechanical brake (crane hoist safety brake) is ancillary to...
Thank you all for the very relevant insights. Will note these points down for the discussion with the vendor design team that will deal with the VFD drives.
As mentioned, we have these issues already worked out and practically tested / certified on our hydraulic drive hoists (in-house design)...
Will look at additional "mechanical brake" arrangements, as suggested.
Each hoist will have 2x Electric motors, each rated at 1500kW. Motor will have a static brake at NDE shaft end and the drive mechanism needs to have a dynamic brake as well, in addition to static brake.
Hi Guys,
Thanks for the comments. Just to be clear, the governing specifications and rules require that the static brake be sized to 150% torque of the drive unit (motor) so they are quite sturdy. However, the same rule requires that the "dynamic brake" bring the load to a stop and the static...
Hi,
I'm a mechanical guy but would appreciate some basic explanation on how to achieve what our team needs to design so I can follow up with a design consultant / vendor who will manage the VFD part of the deal.
In a crane hoist application with electric motors driving the hoist drum via VFD...
Hi,
What would be an acceptable speed for main winch hoist, boom luffing winch and slewing?
I'm reviewing a proposal for a 250T@15m lattice boom crane for offshore, bottom supported application. Thanks.
Hi,
I moved in from Offshore Oil & Gas industry and am new to the marine industry.
Please assist to point me in the right direction as I am preparing an operation manual for a submersible barge to be used for launching vessels (the barger as well as the vesses to be launched are being...
gr2vessels,
Actually, it's to be installed on a self elevating boat and to be used for jetting the silt at sea bed in order to extract the legs from the sea bed after operation. The operating pressure required is 80 bar to dislodge the silt and break-free the suction effect on the leg. If...
Hi, I need to install a sea water jetting pump for a vessel; op. press 80 bar with flow rate 50 m3/hr.
Currently considering piston / plunger type but vendors are unable to quote. Any suitable alternative types? Any recommendd vendors? Thanks.
It would be just a general workshop for maintenance of yard equipment and a few fittings etc. for the production. Most all items come from vendors and directly installed so no major production work. Currently allocated lathe small & medium, milling m/c, grinder, hydraulic press, drill press etc...
Hi, I'm required to set up a machine shop for a small shipyard we are developing. Main function is building new ships apprx. 4000T. Any suggestions on the type of equipment to be installed in the machine shop? Floor area is 25m X 45m (13000 sq. ft). Thanks.