The Locks are very resistant to dust and tolerant of the continuous and frequent grinding they receive and should complete a full working life if treated respectfully and receive some lubrication. Fortress locks are factory lubricated with WD40 or equivalent but have been proven to operate satisfactorily with almost any type of lubricant all the way up to high temperature greases!

To counter problems in the harsh cement and concrete industry, the answer usually lines in the plants themselves! Most concrete product manufacturer have moulds that they need to release their concrete products from, and usually pre-lubricate the mould with diesel oil based mould oil or an environmentally friendly nut or vegetable oil substitute with some additives. A pre lubrication with, or even immersion in, the release agent and subsequent reapplication, should keep Fortress Interlocks working happily for years even where cement is present.

SS and SLS units use a 12W dc solenoid. 110V units incorporate a bridge rectifier. The current will depend on the voltage of the unit: 24V - 500mA (0.5A), 48V - 250mA, 110V - 109mA

It doesn’t matter; the unit will work if the connections are made either way round.

DM, XM & BM. It does not fit DMS, XMS or BMS. There is little point in using a non-Stainless Steel Adaptor with Stainless Steel products. Fortress recommends that the customer makes up pillars for the rare occasions when they may want to mount a stainless steel product behind a panel.

Fortress use Kraus & Naimer (K+N) switches and the stocked switches are shown in the following table:

K&N Switch Type	BS/IEC/VDE current Rating	UL current rating	CSA current rating	Pole configuration	Fortress part number
CA10	20A	20A	16A	4NO	F60999251
CA10	20A	20A	16A	2NO 2NC	F60999230
CA10	20A	20A	16A	4NO 4NC	F60999231
CA25	32A	30A	30A	4NO	F60883
C42	63A	65A	65A	4NO	F60885
C125	50A	150A	150A	4NO	F60999087

 

The differences in current ratings are due to the different approvals – see below. This document refers to the BS/IEC/VDE current ratings throughout.

We will aim to reduce the number of different pole configurations that we purchase. So for example, if a customer asks for a 20A 3NO 3NC or 20A 3NO 1NC, we will supply 20A 4NO 4NC.

The switches are approved to the following:
20A BS, CCC, CSA, GOST, IEC, UL
32A BS, CSA, GOST, IEC, UL
63A BS, CSA, GOST, IEC, UL
150A BS, CSA, GOST, IEC, UL

where
BS = BS EN 60947 (British and EU)
CCC = China Compulsory Certification
CSA = Canadian Standards Association
GOST = Gosudarstvennyj Standard (Russian)
IEC = IEC 60947 – International Electrical Commission (Global)
UL = Underwriters Laboratory (USA)

The switches also conform to some individual European country standards. Details upon request.

According to BS EN 60947-3 the definition of a Switch is:

“A device capable of making, carrying and breaking current within an electrical current under defined conditions”

A Switch Disconnector is defined as:
“A device which complies with the requirements of a switch and also provides off-load isolation in accordance with the specified requirements for safety isolation”

The 4NO versions of the stocked switches will be built as switch disconnectors while the 2NO 2NC and 4NO 4NC versions will just be switches. For specials, all on/off switches (i.e. with NO contacts only) will be built as switch disconnectors and all changeover switches (i.e. with NO and NC contacts) will be built as switches unless otherwise specified.

The Kraus and Naimer switches are all AC but have DC ratings as follows:

 

DC Voltage	20A Switch	32A Switch	63A Switch	150A Switch
24V	20A	32A	63A	150A
48V	12A	25A	50A	150A
60V	4.5A	10A	16A	-
110V	1A	2A	3A	-
220V	0.4A	0.6A	0.7A	-
440V	0.27A	0.3A	-	-

 

This table shows the standard switches and their single pole DC ratings. Higher DC ratings are possible but will require special switches.

Kraus and Naimer switches generally work down to lower currents and voltages than their predecessors. Gold flash contacts will not usually be needed and will NOT be offered without finding out the customer’s EXACT current and voltage requirements. Even if a customer has had gold flash contacts on an old Craig and Derricott switch, that does NOT necessarily mean that he needs gold flash on a Kraus and Naimer switch. The standard 20A switch will work down to 5mA at 20V which is low enough for most safety circuits. If that is not low enough, there is a 6A switch with gold plated contacts that can be offered which will go right down to 1mA at 1V but at greatly increased cost and delivery time.

On the 20A and 32A switches, auxiliary contacts are just extra main contacts so they are rated at 20A and 32A respectively. On the 63A and 125A switches, the auxiliaries are fitted as a separate contact block and rated at 16A. Up to 4 auxiliary contacts can be added to these switches. Auxiliary contacts are intended for operational switching for control, signaling and interlocking purposes and they are not generally considered suitable for safety isolation.

The figures for the rotary switches are listed in the table below:

 

Switch Type	Mechanical Life (No of Operations)	AC-21A Electrical Life (No of Operations)
20A	1,500,000	100,000
32A	1,500,000	100,000
63A	1,500,000	100,000
150A	450,000	75,000

 

The mechanical life of a CL/ML/CLS/MLS is over 1,000,000 operations. This includes DM/DMS, XM/XMS and

BM/BMS products.

The following table list the maximum values:

 

wire type	units	20A	32A	63A	150A
Single core or stranded wire	mm²	2 x 2.5	2 x 6	2 x 16	70
	AWG	2 x 12	2 x 8	2 x 6	2/0
flexible wire	mm²	2 x 2.5	2 x 4	2 x 10	50
	AWG	2 x 14	2 x 10	2 x 6	1/0

 

The 20A, 32A and 63A switches will accept 2 wires per terminal, one either side of the terminal screw, while the 150A switch will accept only one wire per terminal. Only copper wires are to be used.

The wire strip length is the length of wire left exposed at the end of a cable when the insulation is removed. The recommended lengths are shown below.

 

Switch	Strip Length (mm)
20A	8
32A	11
63A	15
150A	20

 

The switches have been tested at 100% of their rated current as follows:
 

Maximum Temperatures
Open to the air at 55°C during 24 hours with peaks up to 60°C
Enclosed at 35°C during 24 hours with peaks up to 40°C
Minimum Temperatures
-5°C under normal use
-25°C if there is no excessive shock or vibration
 

N.B. An incorrectly specified switch can result in excessive internal heating leading to switch malfunction.

The CL range of locks have been tested to -20°C to +40°C. We have in the past produced CL locks that operate up to +150°C, using high temperature grease.