Control Circuit Transformers, 50VA – 2.5kVA | SCL Range

The SCL Range covers control circuit transformers from 50VA to 2.5kVA, designed for industrial control panels, machinery, automation systems and electrical control applications.

Manufactured in the UK by Boardman Transformers, the SCL Range supports common primary voltages including 220V, 230V, 240V, 380V, 400V and 415V, with secondary voltage options including 12V, 24V, 48V, 110V and 230V.

These control circuit transformers are designed and manufactured to comply with IEC / BS-EN 61558 and are suitable for applications requiring dependable voltage transformation within industrial control systems.

This high quality product is manufactured using automated winding and welding machines; they offer good access to the four-hole fixing, touch-proof terminals and full varnish impregnation to protect against humidity.

Key Features

• – Control circuit transformer range
• – Ratings from 50VA to 2.5kVA
• – Designed for industrial control panels and machinery
• – Class 1 isolation transformer with earth screen between primary and secondary
• – Primary voltage options from 220V to 415V
• – Secondary voltage options including 12V, 24V, 48V, 110V and 230V
• – Suitable for 50/60Hz applications
• – Designed and manufactured to comply with IEC / BS-EN 61558
• – UK manufactured by Boardman Transformers

Suitable Applications

The SCL Range is suitable for industrial control applications where a dependable control circuit transformer is required.

• – Industrial control panels
• – Machinery control circuits
• – Automation systems
• – Panel builders
• – OEM electrical assemblies
• – Manufacturing equipment
• – Control circuit voltage transformation
• – Applications requiring 12V, 24V, 48V, 110V or 230V secondary outputs

Control Transformer	Class 1 Isolation Transformer with Earth Screen between Primary and Secondary
Standard	IEC / BS-EN 61558
Primary Voltages	220-230-240-380-400-415V
Secondary Voltages	One of the following. 12V, 24V (12-0-12V), 48V, 110V(55-0-55V), 230V
Frequency	50/60Hz
Insulation Class	B
Insulation Resistance	> 5 Meg Ω
Dielectric Strength	Winding to Earth > 2.5kV
Dielectric Strength	Primary to Secondary > 2.5kV Primary to Earth > 2.5kV Secondary to Earth > 2.5kV
Ambient Temperature	40℃

Transformer Circuit Protection

Transformers must be protected against short circuit and overload.

Primary Circuit

The primary side of the Transformer should be protected against short circuit thereby cutting the supply voltage in the event of a short circuit fault. The rating of the primary protection device has to take into account the high inrush current during energizing of the Transformer.

The table below gives suggested protection values to avoid nuisance tripping on inrush.

Rating VA	Primary Volts	Amps	Fuse	Type C MCB	Type D MCB	Primary Volts	Amps	Fuse	Type C MCB	Type D MCB
50	230	0.21	1	1	1	415	0.12	500mA	1	1
75	230	0.27	1	1	1	415	0.15	500mA	1	1
100	230	0.43	1	2	1	415	0.24	1	1	1
150	230	0.65	2	2	1	415	0.36	1	1	1
200	230	0.86	2	6	2	415	0.48	1	2	1
250	230	1.09	3.15	6	2	415	0.60	2	2	1
300	230	1.2	3.15	6	3	415	0.72	2	2	2
500	230	2.17	4	10	6	415	1.20	3.15	6	4
750	230	3.26	6	10	6	415	1.80	3.15	6	4
1000	230	4.34	8	10	6	415	2.40	5	6	4
1500	230	6.52	10	16	10	415	3.61	6	10	6
2000	230	8.69	12	16	10	415	4.82	10	10	6
2500	230	10.86	16	25	16	415	6.02	10	16	10

Secondary Circuit

The secondary circuit should be protected against short circuit and overload.

The value of the protection should be the same or less than the rated output current.

Part No. VA	A	B	C	D	E	Weight kg	% Reg.	Watts	Inrush VA For 10% Volt Drop	Inrush VA For 5% Volt Drop
SCL25	66	68	77	50	44	0.7	11	6	48	36
SCL50	76	70	86	56	47	1.1	9.8	9	105	77
SCL75	76	76	86	56	53	1.4	8.9	11	135	102
SCL100	84	78	95	64	63	2.2	8.4	14	250	175
SCL150	96	76	102	84	65	3.1	6.7	18	375	260
SCL200	96	86	102	84	72	4	5.8	21	550	375
SCL250	96	101	102	84	90	5	5.6	27	720	470
SCL300	120	88	122	90	73	6	5.3	31	870	585
SCL400	120	100	122	90	85	6.75	5.0	30	1200	790
SCL500	120	120	122	90	106	7.5	4.1	31	1700	1100
SCL750	150	145	140	122	90	8	5.2	60	2200	1475
SCL1000	150	161	140	122	106	13	3.3	67	4000	2500
SCL1500	150	188	140	122	134	16	3.2	88	6200	3850
SCL2000	192	172	180	160	125	18	3.3	100	8060	5030
SCL2500	192	192	180	160	153	24	2.6	120	12100	7300

Voltage Options and Part Number

Winding	Voltage
Primary	220-230-240-380-400-415V
Secondary	0-12V
	24V Centre tapped (12-0-12V)
	0-48V
	110V Centre tapped (55-0-55V)
	0-230V

For a 100VA Transformer with an output of 110V the Part Number would be SCL100110.

Power Rating Calculation

To choose the size of Transformer required for an application the total inrush VA must be calculated. This figure is then applied to the table above with the maximum allowable voltage drop taken into account. For example, for a calculated inrush of 2,100VA the appropriate transformer is as follows:

1. For 10% drop in output volts during inrush, choose 750 VA
2. For 5% drop in output volts during inrush, choose 1000 VA

Consideration must also be given to the continuous VA requirement.

Related Control Transformer Ranges

If the SCL Range is not the right fit for your application, Boardman Transformers also manufactures other control transformer ranges for different ratings, specifications and compliance requirements.

View the MCL Range for alternative 50VA to 2.5kVA control circuit transformer options.

View the CL Range for larger single phase control and industrial transformer applications.